discuss how a buffer solution resists drastic changes in PH when a strong base (OH- )is added to the solution.

Answers

Answer 1

A buffer solution resists drastic changes in pH when a strong base (OH-) is added to the solution due to its ability to maintain a relatively constant pH. A buffer solution resists drastic changes in pH when a strong base is added by neutralizing the added OH- ions and maintaining a relatively constant pH through the reaction of the weak acid and its conjugate base.

1. A buffer solution is made up of a weak acid and its conjugate base (or a weak base and its conjugate acid). When a strong base (OH-) is added to the buffer solution, it reacts with the weak acid in the buffer to form water and the conjugate base of the weak acid.

2. This reaction helps to neutralize the added OH- ions and prevents the pH of the solution from increasing significantly. The weak acid in the buffer acts as a proton donor, combining with the OH- ions to form water.

3. The presence of the conjugate base in the buffer solution also helps to maintain the pH by acting as a proton acceptor. If the pH starts to decrease, the conjugate base can release protons, preventing the pH from dropping too much.

In conclusion, a buffer solution resists drastic changes in pH when a strong base is added by neutralizing the added OH- ions and maintaining a relatively constant pH through the reaction of the weak acid and its conjugate base. This ensures the stability of the solution's pH even in the presence of strong base.

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Related Questions

The rate constant of a first-order reaction is 3.90 × 10−4 s−1 at 350.°C. If the activation energy is 139 kJ/mol, calculate the temperature at which its rate constant is 7.35 × 10−4 s−1.

Answers

The temperature at which its rate constant is 7.35 × 10⁻⁴ s⁻¹ is 637.61 K.

The Arrhenius equation is given as:

k = A × exp(-Ea / (R × T))

Where:

k is the rate constant

A is the pre-exponential factor or frequency factor

Ea is the activation energy

R is the gas constant (8.314 J/(mol·K))

T is the temperature in Kelvin

Given: k1 = 3.90 × 10⁻⁴ s⁻¹

T1 = 350°C

T1 = 350 + 273.15 K

T2 = 623.15 K

From above equation

A = k1 × exp(Ea / (R × T1))

for the temperature (T2):

k2 = 7.35 × 10⁻⁴ s⁻¹

Substituting the values into the equation and solving for T2:

k2 = A × exp(-Ea / (R × T2))

T2 = -Ea / (R × ln(k2 / A))

Substituting the known values into the equation:

Ea = 139 kJ/mol = 139 × 10³ J/mol

R = 8.314 J/(mol·K)

A = k1 × exp(Ea / (R × T1))

Calculating A using the given values of k1

A = (3.90 × 10⁻⁴ ) × exp((139 × 10³) / (8.314 × 623.15 ))

A = (3.90 × 10⁻⁴ ) × 4.484 × 10¹¹

A = 17.487 × 10⁷

T2 = - (139 × 10³ J/mol) / (8.314 × ln((7.35 × 10⁻⁴ ) /17.487  × 10⁷))

T2 = 637.61

Therefore, the temperature at which its rate constant is 7.35 × 10⁻⁴ s⁻¹ is 637.61 K.

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Describe how to prepare 100 ml of 5.0 N NaH2PO4 (m.w. 120g,
valence =3)

Answers

To prepare 100 ml of 5.0 N NaH2PO4 solution, dissolve 60 grams of NaH2PO4 in distilled water and bring the volume to 100 ml in a volumetric flask.

To prepare 100 ml of 5.0 N NaH2PO4 solution:

1. Calculate the amount of NaH2PO4 needed using the formula:

  Amount (in moles) = Normality (N) * Volume (in liters)

  Amount = 5.0 N * 0.1 L = 0.5 moles

2. Calculate the mass of NaH2PO4 using its molar mass:

  Mass = Amount (in moles) * Molar mass

  Mass = 0.5 moles * 120 g/mol = 60 g

3. Weigh 60 grams of NaH2PO4 using an analytical balance.

4. Dissolve the weighed NaH2PO4 in distilled water and transfer it to a 100 ml volumetric flask.

5. Add distilled water to the volumetric flask until the volume reaches the mark (100 ml).

6. Mix the solution thoroughly to ensure uniform concentration.

You have now prepared 100 ml of 5.0 N NaH2PO4 solution.

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An analyst is taking absorbance readings on a sample that is nominally 0.1Min Co2+. The first sample reading she obtains is 5.766. To get an accurate concentration for her sample, her next logical action would be to: Take another sample because this one most likely contains an interferent Dilute the sample Rotovap the sample to increase its concentration Record the absorbance value in her lab notebook and use Beer's law to calculate the concentration Use a higher quality spectrometer

Answers

The next logical step for the analyst to take to obtain an accurate concentration for her sample would be to take another sample because this one most likely contains an interferent.

The next logical action for the analyst to get an accurate concentration for her sample would be to take another sample because this one most likely contains an interferent. The first reading obtained by the analyst is 5.766, which is far outside the range of 0.1M of CO2+. An interferent could be the cause of this result, and an additional sample is required to verify that this is not the case. When there is an interferent present in the sample, the accuracy of a spectrometer reading is compromised. If the sample was undiluted, diluting it can help to increase the concentration of the sample and make it easier to determine an accurate absorbance reading.

Using Beer's law and calculating the concentration would be ideal if the sample was diluted, and the analyst is confident that there is no interferent present. It is not necessary to use a higher-quality spectrometer because the one that is presently being used is sufficient. Therefore, the next logical step for the analyst to take to obtain an accurate concentration for her sample would be to take another sample because this one most likely contains an interferent.

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What is the equilibrium constant K for a reaction which has ΔrG° = 7.4 kJ mol-1 , valid at a temperature of 33.3 °C? Express your answer to at least 2 significant figures. Remember: if you want to express an answer in scientific notation, use the letter "E". For example "4.32 x 104" should be entered as "4.32E4".

Answers

The equilibrium constant (K) for the reaction, given ΔrG° = 7.4 kJ mol⁻¹ at a temperature of 33.3 °C, is approximately 3.49E2.

The relationship between the standard Gibbs free energy change (ΔrG°) and the equilibrium constant (K) is given by the equation ΔrG° = -RT ln(K), where R is the gas constant and T is the temperature in Kelvin.

To calculate K, we need to rearrange the equation as K = e(-ΔrG°/RT), where e represents the base of the natural logarithm.

ΔrG° = 7.4 kJ mol⁻¹

Temperature (T) = 33.3 °C = 33.3 + 273.15 = 306.45 K

Substituting the values into the equation, we get:

K = e(-7.4E3 J mol⁻¹ / (8.314 J K⁻¹ mol⁻¹ * 306.45 K))

Using a calculator, we find K ≈ 3.49E2.

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If a batch of solid KOH pellets is only 84% pure and you wish to
prepare 250 ml of 0.5N KOH, how many grams should you weigh and
dilute to 250ml?

Answers

To determine the amount of KOH pellets needed to prepare 250 ml of KOH with a normality of 0.5, we need to consider the purity of the KOH pellets.

Given that the KOH pellets are 84% pure, we can calculate the amount of pure KOH in the pellets as follows:

Mass of pure KOH = 0.84 (84%) x Total mass of KOH pellets

Next, we can calculate the moles of KOH required for the desired concentration:

Moles of KOH = 0.5 N x 0.25 L (250 ml) = 0.125 moles

Now, we can determine the molar mass of KOH:

Molar mass of KOH = 39.10 g/mol + 16.00 g/mol + 1.01 g/mol = 56.11 g/mol

Finally, we can calculate the mass of KOH pellets needed:

Mass of KOH pellets = (Moles of KOH x Molar mass of KOH) / Mass % of pure KOH

Mass of KOH pellets = (0.125 moles x 56.11 g/mol) / 0.84

Mass of KOH pellets = 8.342 g

Therefore, you should weigh approximately 8.342 grams of KOH pellets and dilute them to 250 ml to prepare a 0.5N KOH solution.

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pour reaction A(aq) ---> B(ag) the variation in the standard free enthalpy is 3.49 kJ at 25°C and 4.88 kJ at 45°C. Calculate it value of the equilibrium constant for this reaction at 75°C. Issue 2: With a container containing 31.0 g of CO2(g). The partial pressure of CO2 is 2.74 atm and the volume of the container is 30.5 L. What is the mean square velocity (in m/s) of the CO2 molecules in this container? issue 3 On 500.0 mL of a buffer solution of 0.653 M in NH and 0.354 M in NH4Cl. On Add 500.0 ml of a 0.219 M solution in HCl. The final volume is 1.0000 L. The value of K, for NH; is 1.8 x 10-5. What is the final pH of this solution?

Answers

The equilibrium constant at 75°C is approximately 139,353.

The mean square velocity of CO₂ molecules in the container is approximately 449 m/s.

The final pH of the solution is approximately 4.32.

How to solve for equilibrium, mean and pH?

Issue 1: To calculate the equilibrium constant (K) at 75°C for the reaction A(aq) → B(ag), use the Van 't Hoff equation, which relates the change in standard free enthalpy (∆G°) with temperature (T) and the equilibrium constant (K).

ln(K2/K1) = (∆H°/R) × (1/T1 - 1/T2)

Where K1 = equilibrium constant at T1 (25°C), K2 = equilibrium constant at T2 (75°C), ∆H° = change in standard enthalpy, R = gas constant (8.314 J/(molK)), T1 = initial temperature (25°C + 273.15 = 298.15 K), and T2 = final temperature (75°C + 273.15 = 348.15 K).

Substituting the given values:

ln(K2/1) = (3.49 kJ × 1000 J/kJ / 8.314 J/(molK)) × (1/298.15 K - 1/348.15 K)

Simplifying the equation and solving for ln(K2):

ln(K2) = 11.85

Now, calculate K2 by taking the exponential of both sides:

K2 = [tex]e^{(11.85)}[/tex] ≈ 139,353

Therefore, the equilibrium constant at 75°C is approximately 139,353.

Issue 2: To calculate the mean square velocity of CO₂ molecules, use the following equation:

v² = (3RT) / M

Where v = mean square velocity, R = gas constant (0.0821 L·atm/(mol·K)), T = temperature in Kelvin (convert from °C to K), and M = molar mass of CO₂ (44.01 g/mol).

Substituting the given values:

v² = (3 × 0.0821 L·atm/(mol·K) × (273.15 + 45) K) / 44.01 g/mol

Simplifying the equation and calculating the square root:

v ≈ 449 m/s

Therefore, the mean square velocity of CO₂ molecules in the container is approximately 449 m/s.

Issue 3: To calculate the final pH of the solution, consider the dissociation of NH₃ and NH₄Cl in water. NH₃ acts as a weak base, while NH₄Cl acts as its conjugate acid.

NH₃ + H₂O ↔ NH₄⁺ + OH⁻

Use the Henderson-Hasselbalch equation to calculate the pH:

pH = pKa + log([A-]/[HA])

Where pKa = negative logarithm of the acid dissociation constant (Ka), [A-] = concentration of the conjugate base (NH₄⁺), and [HA] = concentration of the weak acid (NH₃).

Initially, buffer solution of NH₃ and NH₄Cl, so the concentrations are as follows:

[A-] = 0.354 M

[HA] = 0.653 M

After adding the HCl solution, the following changes:

[A-] = 0.354 M

[HA] = 0.653 M - 0.219 M = 0.434 M

The pKa for NH₃ is given as 1.8 x 10⁻⁵.

Substituting the values into the Henderson-Hasselbalch equation:

pH = -log(1.8 x 10⁻⁵) + log(0.354/0.434)

Calculating the pH:

pH ≈ 4.32

Therefore, the final pH of the solution is approximately 4.32.

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2. [25 pts] Sketch a conformational analysis curve (potential energy vs rotation curve) showing the energy changes and the conformational arrangement of groups using a Newman projection technique that

Answers

A conformational analysis curve can be sketched to represent the potential energy changes and the conformational arrangement of groups using a Newman projection technique.

Conformational analysis is a useful tool for studying the energy changes and conformational arrangements of groups in a molecule. The analysis is often represented graphically as a conformational analysis curve, which plots the potential energy of the molecule as a function of rotation around a specific bond.

To sketch the conformational analysis curve using a Newman projection technique, follow these steps:

1. Choose the bond of interest: Select the bond that you want to analyze and represent it as a Newman projection.

2. Define the torsion angle: Determine the torsion angle (dihedral angle) between the two groups attached to the selected bond.

3. Rotate the groups: Start with one conformation and rotate the groups around the bond by a certain angle, typically in increments of 10 or 15 degrees.

4. Calculate the potential energy: At each rotated conformation, calculate the potential energy of the molecule using computational methods or experimental data.

5. Plot the curve: Plot the potential energy values on the y-axis and the torsion angle on the x-axis to create the conformational analysis curve.

6. Interpret the curve: Analyze the curve to understand the energy changes and the conformational arrangements of the groups. The lowest energy conformation corresponds to the most stable arrangement, while the higher energy conformations represent less stable or higher-energy states.

By sketching the conformational analysis curve using a Newman projection technique, one can visualize and analyze the energy changes and conformational arrangements of groups in a molecule. The curve provides insights into the preferred conformations and the relative stability of different molecular arrangements.

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What is the mole fraction of methanol (CH3OH, molar mass = 32.04 g/mol) in a 8.697 mol/kg solution of methanol in water Question 9 Which of the following aqueous solutions will have the lowest freezing point? O 0.50 m MgSO4 0.50 m FeCl3 O 1.00 m glucose (C6H1206) 0.50 m CuCl₂ O 0.50 m KNO3 Question 10 1 pts Calculate the highest theoretically possible boiling point elevation for a solution made by dissolving 11.9 g of Fe(NO3)3 in 25.0 g of H₂O. Kb(H₂O) = 0.52 °C/m. Tb (H₂O) = 100.00 °C Molar mass of Fe(NO3)3: 241.86 g/mol 1 pts

Answers

9- the aqueous solution with the lowest freezing point is 0.50 m MgSO₄.

10-the highest theoretically possible boiling point elevation for the solution is 0.0184 °C.

9- To determine which aqueous solution will have the lowest freezing point, we need to consider the concentration of solute particles in each solution.

We can compare the number of solute particles each option provides when dissolved in water.

1. For 0.50 m MgSO₄:

MgSO₄ dissociates into three ions: Mg²⁺ and SO₄²⁻.

2. For 0.50 m FeCl₃:

FeCl₃ dissociates into four ions: Fe³⁺ and 3Cl⁻.

3. For 1.00 m glucose (C₆H₁₂O₆):

Glucose does not dissociate into ions in water, so it remains as individual molecules.

4. For 0.50 m CuCl₂:

CuCl₂ dissociates into three ions: Cu²⁺ and 2Cl⁻.

Since the freezing point depression depends on the

concentration of solute particles, the solution with the highest number of solute particles will have the lowest freezing point. Comparing the options, 0.50 m FeCl₃ provides the highest number of solute particles with four ions, followed by 0.50 m MgSO₄ with three ions. The other options, 1.00 m glucose and 0.50 m CuCl₂, do not dissociate into ions and thus have fewer solute particles.

10- To calculate the highest theoretically possible boiling point elevation, we can use the formula:

ΔTb = Kb * molality

Mass of Fe(NO₃)₃ = 11.9 g

Molar mass of Fe(NO₃)₃ = 241.86 g/mol

Mass of H₂O = 25.0 g

Kb(H₂O) = 0.52 °C/m

First, calculate the moles of Fe(NO₃)₃:

moles = mass / molar mass

moles = 11.9 g / 241.86 g/mol = 0.0492 mol

Next, calculate the moles of H₂O:

moles = mass / molar mass

moles = 25.0 g / 18.02 g/mol = 1.387 mol

Now, calculate the molality (m) of the solution:

m = moles of solute / mass of solvent in kg

m = 0.0492 mol / 1.387 kg = 0.0354 mol/kg

Finally, calculate the boiling point elevation:

ΔTb = Kb * molality

ΔTb = 0.52 °C/m * 0.0354 mol/kg = 0.0184 °C

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A patient is given 0.050 mgmg of technetium-99 mm (where m means metastable—an unstable but long-lived state), a radioactive isotope with a half-life of about 6.0 hours.
How long until the radioactive isotope decays to 3.1×10−3 mgmg ?
Express your answer using two significant figures.

Answers

The time taken for technetium-99m to decay to 3.1 × 10⁻³ mgmg is 25.4 hours.

The amount of technetium-99m present in the sample is 0.050 mgmg. A half-life of 6.0 hours is associated with the radioactive isotope, which means that the amount of technetium-99m present will halve every 6.0 hours. The quantity of technetium-99m remaining after any number of half-lives is given by the equation: [tex]N = N₀(1/2)^n where N₀[/tex] is the original quantity, N is the quantity remaining after n half-lives, and n is the number of half-lives that have occurred.

Thus, the amount of technetium-99m remaining in the sample is 3.1 × 10⁻³ mgmg, and we want to determine how many half-lives have occurred until this point. Let's plug in the numbers: [tex]N = N₀(1/2)^n3.1 × 10⁻³ = 0.050(1/2)^nn[/tex]

= 4.23 Half-lives have elapsed, indicating that the quantity of technetium-99m has halved 4.23 times. Since each half-life is 6.0 hours long, the elapsed time is (4.23 × 6.0) ≈ 25.4 hours.

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S + 6 HNO3 → H2SO4 + 6 NO2 + 2 H2O

In the above equation, how many grams of water can be made when 14.5 moles of HNO3 are consumed?

Round your answer to the nearest tenth. If you answer is a whole number like 4, report the answer as 4.0

Use the following molar masses. If you do not use these masses, the computer will mark your answer incorrect.:

Element Molar Mass
Hydrogen 1
Nitrogen 14
Sulfur 32
Oxygen 16

Answers

Answer:

            33.63 g H₂O

Explanation:

The mole ratio of HNO₃ and H₂O is 6 : 2

Hence, 16.9 moles of HNO₃ will produce = 2/6×5.6 = 1.86 moles of H₂O

Also,

Mass = Moles × M.Mass

Mass = 1.86 mol × 18.02 g/mol

Mass = 33.63 g H₂O

Must be a minimum of 250 words:
Describe the difference between ionic, covalent and metallic bonds. To show how each is different and important in everyday life in its own way, find an example of each you use or come in contact with frequently.

Answers

Ionic bonds involve the transfer of electrons between atoms, covalent bonds involve the sharing of electrons, and metallic bonds involve a sea of delocalized electrons.

Ionic bonds occur when there is a transfer of electrons from one atom to another, resulting in the formation of positively charged ions (cations) and negatively charged ions (anions). An example of an ionic bond in everyday life is table salt (sodium chloride, NaCl).

Sodium donates an electron to chlorine, resulting in the formation of Na+ and Cl- ions. These oppositely charged ions attract each other, forming a crystalline structure that we use as a seasoning for food.

Covalent bonds involve the sharing of electrons between atoms. In this type of bond, two or more atoms share electrons to achieve a stable electron configuration. Water (H2O) is an example of a substance held together by covalent bonds. Oxygen shares electrons with two hydrogen atoms, resulting in a molecule with polar properties.

This polarity allows water to exhibit properties like high boiling point, surface tension, and the ability to dissolve many substances, making it essential for various biological and chemical processes.

Metallic bonds occur in metals, where positively charged metal ions are surrounded by a sea of delocalized electrons. These electrons are free to move within the structure, creating a strong bond.

An example of a metallic bond is seen in copper (Cu) wiring used in electrical applications. The delocalized electrons allow for efficient flow of electric current through the metal, making copper an excellent conductor.

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Classify each of the following complexes as either paramagnetic or diamagnetic: [V(OH 2

) 6

] 3+
,[MnF 6

] 2−
Select one: [V(OH 2

) 6

] 3+
is diamagnetic and [MnF 6

] 2−
is paramagnetic [V(OH 2

) 6

] 3+
is paramagnetic and [MnF 6

] 2−
is diamagnetic Both are paramagnetic Both are diamagnetic There is not enough information Which of the following complexes is/are likely to be coloured? [Cr(CN) 6

] 4−
,[Zn(NH 3

) 6

] 2+
,[Cu(OH 2

) 6

] 2+
Select one: [Cu(OH 2

) 6

] 2+
only [Cr(CN) 6

] 4−
and [Cu(OH 2

) 6

] 2+
only [Zn(NH 3

) 6

] 2+
only [Zn(NH 3

) 6

] 2+
and [Cu(OH 2

) 6

] 2+
only None are coloured

Answers

- [V(OH2)6]3+ is paramagnetic. - [MnF6]2- is paramagnetic.

- [Cr(CN)6]4- is likely to be colored. - [Zn(NH3)6]2+ is not likely to be colored. - [Cu(OH2)6]2+ is likely to be colored.

To determine the paramagnetic or diamagnetic nature of a complex, we need to consider the electronic configuration and the presence of unpaired electrons in the complex.

1. [V(OH2)6]3+:

The vanadium ion in [V(OH2)6]3+ has the electron configuration [Ar]3d3. It has three unpaired electrons, which indicates the presence of unpaired spins and makes the complex paramagnetic.

2. [MnF6]2-:

The manganese ion in [MnF6]2- has the electron configuration [Ar]3d5. It has five unpaired electrons, indicating the presence of unpaired spins and making the complex paramagnetic.

Regarding the color of the complexes:

1. [Cr(CN)6]4-:

The presence of the cyanide ligands in [Cr(CN)6]4- suggests that it is likely to be colored. Cyanide ligands are known to produce intense color in coordination complexes.

2. [Zn(NH3)6]2+:

The zinc ion in [Zn(NH3)6]2+ has a full d-orbital (d10) electronic configuration, indicating the absence of unpaired electrons. Generally, complexes with completely filled d-orbitals, like Zn2+, do not exhibit color.

3. [Cu(OH2)6]2+:

The copper ion in [Cu(OH2)6]2+ has the electron configuration [Ar]3d9. It has one unpaired electron, indicating the presence of unpaired spins. Copper complexes often exhibit vivid colors due to d-d electronic transitions.

- [V(OH2)6]3+ is paramagnetic.

- [MnF6]2- is paramagnetic.

- [Cr(CN)6]4- is likely to be colored.

- [Zn(NH3)6]2+ is not likely to be colored.

- [Cu(OH2)6]2+ is likely to be colored.


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A chemistry student weighs out 0.151 g of lactic acid (HC3H₂O3) into a 250. mL volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with 0.1900 M NaOH solution

Answers

The volume of 0.1900 M NaOH solution required to neutralize 0.151 g of lactic acid (HC3H₂O3) in a 250 mL volumetric flask.

To determine the volume of 0.1900 M NaOH solution required to neutralize the lactic acid (HC3H₂O3), we need to calculate the number of moles of lactic acid and use the stoichiometry of the reaction.

The balanced equation for the reaction between lactic acid and NaOH is:

HC3H₂O3 + NaOH -> NaC3H₃O₃ + H2O

From the equation, we can see that 1 mole of lactic acid reacts with 1 mole of NaOH to produce 1 mole of sodium lactate and 1 mole of water.

First, let's calculate the number of moles of lactic acid given the mass provided:

Mass of lactic acid = 0.151 g

Molar mass of lactic acid (HC3H₂O3) = 3(12.01 g/mol) + 6(1.01 g/mol) + 3(16.00 g/mol) = 90.08 g/mol

Number of moles of lactic acid = Mass of lactic acid / Molar mass of lactic acid

= 0.151 g / 90.08 g/mol

Since the student diluted the lactic acid to a total volume of 250 mL, we can assume the molarity of the lactic acid solution is equal to the molarity of the lactic acid itself.

Now, let's use the stoichiometry to determine the volume of NaOH solution required to neutralize the lactic acid.

Moles of NaOH = Moles of lactic acid (HC3H₂O3) (from the balanced equation)

Volume of NaOH solution (L) = Moles of NaOH / Molarity of NaOH

Finally, we can convert the volume to milliliters:

Volume of NaOH solution (mL) = Volume of NaOH solution (L) * 1000 mL/L

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1. A coffee cup calorimeter having a heat capacity of \( 451 \mathrm{~J} /{ }^{\circ} \mathrm{C} \) was used to measure the heat evolved when \( 100 \mathrm{ml} \) of \( 1 \mathrm{M} \mathrm{NaOH}(\ma

Answers

ΔH in J/mol of H2O produced by the reaction is 34.1 kJ/mol H2O.

A coffee cup calorimeter having a heat capacity of 451 J/°C was used to measure the heat evolved when 100 mL of 1 M NaOH (aqueous) at 24.6°C was mixed with 100 mL of 1 M HCl (aqueous) at 24.6°C.

The temperature rose to 32.2°C. The density of each solution was 1.00 g/mL. Using the data given, determine ΔH in J/mol of H2O produced by the reaction. Assume that the specific heat capacity of each solution is equal to the specific heat capacity of water.

Calculate the heat transferred from the reaction:

Heat transferred = C (calorimeter) * ΔT

Heat transferred = (451 J/°C)(32.2°C - 24.6°C)

Heat transferred = 3408 J

Calculate the moles of HCl reacted:

1 M HCl = 1 mole HCl / 1 liter of solution

100 mL HCl * (1 liter / 1000 mL) = 0.100 L

1 mole / liter = x mole / 0.100 L

x = 0.100 moles

Use stoichiometry to calculate the moles of NaOH reacted:

[tex]NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)[/tex]

1 mole HCl = 1 mole NaOH

0.100 moles HCl = 0.100 moles NaOH

Calculate the heat per mole of H2O produced:

3408 J / (0.100 mol H2O) = 34.1 kJ/mol H2O

Therefore, ΔH in J/mol of H2O produced by the reaction is 34.1 kJ/mol H2O.

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Predict the major product from the treatment of isopropoxybenzene with bromine and iron(III) bromide. Draw the full mechanism for the reaction, using appropriate arrows to indicate electron movement and full structure i.e resonance forms of any intermidiates.

Answers

The major product from the treatment of isopropoxybenzene with bromine and iron (III) bromide is 2-bromo-1-(1-methylethoxy)benzene.

This is because when isopropoxybenzene is reacted with Br2 and FeBr3, the bromine is replaced by the isopropoxy group to yield 2-bromo-1-(1-methylethoxy)benzene.

Below is the full mechanism of the reaction of isopropoxybenzene with bromine and iron (III) bromide:

Step 1: Formation of the electrophilic species

FeBr3 + Br2 → FeBr4^- + Br+

Step 2: Electrophilic attack by Br+ on isopropoxybenzene

Br+ attacks the benzene ring of isopropoxybenzene to form the arenium ion intermediate.

Step 3: Deprotonation of the arenium ion to form intermediate A

Intermediate A is formed by proton transfer from carbon to oxygen. The intermediate A can exist as a pair of resonance structures.

Step 4: Bromination of intermediate A

Intermediate A undergoes bromination at the ortho position since it is activated by the methoxy group.

Step 5: Deprotonation of the arenium ion to form the final product

Intermediate B is formed by proton transfer from carbon to oxygen. The intermediate B can exist as a pair of resonance structures.

2-bromo-1-(1-methylethoxy)benzene is the final product.

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An Honours students is performing a literature reaction (i.e.
one reported to work), but it is not producing the desired
products. The supervisor suggests that they try performing the
reaction at lowe

Answers

Lowering the temperature in a literature reaction that is not producing desired products can help slow down the reaction rate, improve selectivity, and optimize conditions for achieving the desired outcome.

An Honours student is conducting a literature reaction that is not yielding the desired products. In response, the supervisor suggests attempting the reaction at a lower temperature.

Lowering the temperature can have several effects on a chemical reaction. It can slow down the reaction rate, which may be beneficial if the reaction is occurring too quickly or leading to undesired side reactions.

Lower temperatures can also favor specific reaction pathways or increase the stability of reactive intermediates, potentially improving the selectivity or yield of the desired products.

By reducing the temperature, the student may gain insight into the reaction kinetics and optimize the conditions to achieve the desired outcome.

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What is the formula weight of magnesium acetate in grams per mole?

Answers

The formula weight of magnesium acetate is 86.375 grams per mole.

The formula weight of magnesium acetate (Mg(CH3COO)2) is calculated by adding up the atomic masses of all the atoms in the formula.

The formula weight is also known as the molar mass or molecular weight and is expressed in grams per mole (g/mol). It represents the mass of one mole of a substance.

In the case of magnesium acetate, we have:

- Magnesium (Mg) with an atomic mass of 24.305 g/mol

- Carbon (C) with an atomic mass of 12.011 g/mol

- Hydrogen (H) with an atomic mass of 1.008 g/mol

- Oxygen (O) with an atomic mass of 16.00 g/mol

The formula weight, we multiply the atomic mass of each element by the number of atoms present in the formula and sum up the results.

For magnesium acetate, we have:

- 2 carbon atoms (2 * 12.011 g/mol = 24.022 g/mol)

- 6 hydrogen atoms (6 * 1.008 g/mol = 6.048 g/mol)

- 4 oxygen atoms (4 * 16.00 g/mol = 64.00 g/mol)

- 1 magnesium atom (1 * 24.305 g/mol = 24.305 g/mol)

Summing up these values, we get:

24.022 g/mol + 6.048 g/mol + 64.00 g/mol + 24.305 g/mol = 118.375 g/mol

Therefore, the formula weight of magnesium acetate is 118.375 grams per mole.

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Set up the partial reaction equations (Ox, Red) and summed up the redox-reaction of the below’s reactions. Also, determine the oxidation numbers of all reactants.
1) Mercury reacts with nitric acid to mercury(II)-ions, nitrogen monoxide and water.
2) Iron(III)-ions react with iodine to iodide and iron(II)-ions.
3) In the presence of sulfuric acid, potassium permanganate reacts with iron(II)-sulfate to potassium sulfate, manganese(II)-sulfate, iron(III)- sulfate, and water.

Answers

1) Overall redox-reaction:

[tex]Hg + 2HNO_3 -- > Hg_2^+ + N_2O + 3H_2O[/tex]

Oxidation numbers:

In Hg: The oxidation number of Hg changes from 0 to +2.

In HNO₃: The oxidation number of N changes from +5 to +2, and the oxidation number of O changes from -2 to 0.

2) Overall redox-reaction:

[tex]2Fe_3^+ + I_2 -- > 2Fe_2^+ + 2I^-[/tex]

Oxidation numbers:

In Fe₃⁺: The oxidation number of Fe changes from +3 to +2.

In I₂: The oxidation number of I changes from 0 to -1.

3) Overall redox-reaction:

[tex]5Fe_2^+ + MnO_4^- + 8H^+ -- > 5Fe_3^+ + Mn_2^+ + 4H_2O[/tex]

Oxidation numbers:

In Fe₂⁺: The oxidation number of Fe changes from +2 to +3.

In MnO₄⁻: The oxidation number of Mn changes from +7 to +2, and the oxidation number of O changes from -2 to -2.

1) Mercury reacts with nitric acid to mercury(II)-ions, nitrogen monoxide, and water.

Partial reaction equations:

Oxidation half-reaction (Ox): [tex]Hg -- > Hg_2^+ + 2e^-[/tex]

Reduction half-reaction (Red): [tex]2HNO_3 + 2e^- -- > N_2O + 3H_2O[/tex]

Overall redox-reaction:

[tex]Hg + 2HNO_3 -- > Hg_2^+ + N_2O + 3H_2O[/tex]

Oxidation numbers:

In Hg: The oxidation number of Hg changes from 0 to +2.

In HNO₃: The oxidation number of N changes from +5 to +2, and the oxidation number of O changes from -2 to 0.

2) Iron(III)-ions react with iodine to iodide and iron(II)-ions.

Partial reaction equations:

Oxidation half-reaction (Ox): [tex]Fe_3^+ -- > Fe_2^+ + e^-[/tex]

Reduction half-reaction (Red): [tex]I_2 + 2e^- -- > 2I^-[/tex]

Overall redox-reaction:

[tex]2Fe_3^+ + I_2 -- > 2Fe_2^+ + 2I^-[/tex]

Oxidation numbers:

In Fe3+: The oxidation number of Fe changes from +3 to +2.

In I2: The oxidation number of I changes from 0 to -1.

3) In the presence of sulfuric acid, potassium permanganate reacts with iron(II)-sulfate to potassium sulfate, manganese(II)-sulfate, iron(III)-sulfate, and water.

Partial reaction equations:

Oxidation half-reaction (Ox): [tex]Fe_2^+ - > Fe_3^+ + e^-[/tex]

Reduction half-reaction (Red): [tex]MnO_4^- + 8H^+ + 5e^- -- > Mn_2^+ + 4H_2O[/tex]

Overall redox-reaction:

[tex]5Fe_2^+ + MnO_4^- + 8H^+ -- > 5Fe_3^+ + Mn_2^+ + 4H_2O[/tex]

Oxidation numbers:

In Fe₂⁺: The oxidation number of Fe changes from +2 to +3.

In MnO₄⁻: The oxidation number of Mn changes from +7 to +2, and the oxidation number of O changes from -2 to -2.

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What is the equilibrium constant expression for the following equation at equilititum? (Pay carefut utherition to the phane indicatorsl) 2HCl(g)+Mg(OH)2​( s)∈/MgCl2​(aq)+2H2​O(t) a. ε4​=[MgCl2​]×[H2​O2[HCl3×[Mgg​(OH)2​]​ b. αc​=[HCl2×[Mg(OH)2​][MgCl2​]×[H2​O]2​ κt​=[MgCl2​][HCl2​ d. Kc​=[HCl2[MgCl2​]​ Kc​=[HCl]×[Mg(OH)2​][MgCl2​]×[H2​O]​

Answers

The equilibrium constant expression for the given equation at equilibrium is Kc​ = [HCl]²/[Mg(OH)₂][MgCl₂][H₂O]². The correct option is d.

The equilibrium constant expression is derived from the balanced chemical equation at equilibrium, where the coefficients of the reactants and products are used as exponents in the expression.

In the given equation, 2HCl(g) + Mg(OH)₂(s) → MgCl₂(aq) + 2H₂O(l), the equilibrium constant expression is determined by taking the concentrations of the products divided by the concentrations of the reactants, each raised to the power of their respective coefficients.

Therefore, the equilibrium constant expression for the given equation is Kc​ = [HCl]²/[Mg(OH)₂][MgCl₂][H₂O]².

This expression shows that the equilibrium constant (Kc) is calculated by squaring the concentration of HCl and dividing it by the product of the concentrations of Mg(OH)₂, MgCl₂, and the square of the concentration of H₂O. The correct answer is option D.

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what does the number prefix tell you in the name of a branched alkane?
A) The position of the double bond
B) The position of the single bond
C) The position of the functional group
D) The position of the triple bond
correct answer is C)

Answers

In the name of a branched alkane, the number prefix tells you the position of the functional group. A branched alkane is a type of organic molecule that has a carbon chain with one or more branches or side chains attached to it. The side chains can be functional groups like hydroxyl, amino, or carboxyl groups or simple alkyl chains like methyl or ethyl groups.

The naming system used for branched alkanes is called the IUPAC system, which stands for the International Union of Pure and Applied Chemistry. This system uses a prefix to indicate the number of carbon atoms in the longest continuous chain of carbon atoms in the molecule. The prefix is followed by the suffix "-ane" to indicate that the molecule is an alkane.The prefix also indicates the position of any side chains or functional groups that are attached to the carbon chain. The position is indicated by a number that corresponds to the location of the side chain or functional group on the carbon chain. For example, in the name "2-methylpentane", the prefix "pent" indicates that there are five carbon atoms in the longest continuous chain, the number "2" indicates that the methyl group is attached to the second carbon atom, and the suffix "-ane" indicates that the molecule is an alkaneIn summary, the number prefix in the name of a branched alkane indicates the position of the functional group or side chain on the carbon chain. This is an important aspect of organic chemistry as it allows chemists to accurately identify and name organic molecules.

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choices for 17 are 1H, 2H, 3H, 6H, 9H for all blanks
You will use the below spectral information to determine the structure of the molecule: Formula: \( \mathrm{C}_{7} \mathrm{H}_{14} \mathrm{O}_{2} \) IR: "H NMR: Note the following peaks: 0.82ppm: sing

Answers

The structure of the molecule includes a single methyl group (CH₃).

Based on the given information, we need to determine the structure of a molecule with the formula C₇H₁₄O₂, using the provided spectral information. Let's analyze the options for the blank.

IR: "H NMR: Note the following peaks: 0.82 ppm: sing"

The singlet peak at 0.82 ppm in the 1H NMR spectrum indicates the presence of a methyl group (CH₃) in the molecule. Since there is no information about any other peaks in the 1H NMR spectrum or additional spectral data, we can focus on identifying the methyl group.

Out of the options given (1H, 2H, 3H, 6H, 9H), the correct choice for the blank is "1H" because a singlet peak corresponds to a single proton (H) in the molecule. Therefore, the structure of the molecule includes a single methyl group (CH₃).

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--The given question is incomplete, the complete question is

"Choices for 17 are 1H, 2H, 3H, 6H, 9H for all blanks. You will use the below spectral information to determine the structure of the molecule: Formula: \( \mathrm{C}_{7} \mathrm{H}_{14} \mathrm{O}_{2} \) IR: "H NMR: Note the following peaks: 0.82ppm: sing.

A putrified fossil around 3000 years old is sent to a geology lab for experiment. As a lab geologist you are asked to calculate the contamination in the sample.You performed an experiment and after incubating the sample at 35 celcius you found out total 120,000 bacterial colonies .Dilute the sample 1000 times and calculate the TBC ?

Answers

After diluting the sample 1000 times , the  bacterial count (TBC) in the putrefied fossil sample is estimated to be 120 colony-forming units per milliliter (CFU/ml).

To dilute the sample by a factor of 1000, we can take 1 ml of the original sample and add it to 999 ml of a diluent. This dilution ratio of 1:1000 ensures that the concentration of bacteria in the sample is significantly reduced.

To calculate the TBC, we can use the formula:

TBC = (CFU / Dilution Factor) * Reciprocal of Volume Plated

CFU: Colony Forming Units (original count)

Dilution Factor: 1000 (due to the 1:1000 dilution)

Reciprocal of Volume Plated: In this case, let's assume 0.1 ml was plated (as an example)

Using these values, we can calculate the TBC as follows:

TBC = (120,000 CFU / 1000) * (1 / 0.1 ml)

TBC = 120 CFU/ml

Therefore, after diluting the sample 1000 times, the  bacterial count (TBC) in the putrefied fossil sample is estimated to be 120 colony-forming units per milliliter (CFU/ml).

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Which of the following bases are strong enough to deprotonate CH 3

CH 2

CH 2

C≡CH(pK a

=25), so that equilibrium favors the products? NaC≡N C 6

H 5

Li NaOH NaNH 2

NaCH 2

(CO)N(CH 3

) 2

H 2

O

Answers

Among the given bases, [tex]NaNH_2[/tex] (sodium amide) and [tex]NaCH_2(CO)N(CH_3)_2[/tex] (sodium diisopropylamide or LDA) are strong enough to deprotonate [tex]CH_3CH_2CH_2C \equiv CH[/tex] (propyne) and favor the products.

To determine which bases are strong enough to deprotonate propyne[tex](CH_3CH_2CH_2C \equiv CH[/tex]), we need to compare their basicity or ability to accept a proton ([tex]H^+[/tex]). The stronger the base, the more likely it is to deprotonate the compound and shift the equilibrium towards the products.

Sodium amide ([tex]NaNH_2[/tex]) and sodium diisopropylamide ([tex]NaCH_2(CO)N(CH_3)_2[/tex] or LDA) are strong bases commonly used in organic chemistry. They are capable of deprotonating alkynes such as propyne. On the other hand, NaC≡N (sodium cyanide), NaOH (sodium hydroxide), and C6H5Li (phenyllithium) are not strong enough to deprotonate propyne.

Overall, only [tex]NaNH_2[/tex] and [tex]NaCH_2(CO)N(CH_3)_2[/tex] are strong bases that can deprotonate propyne and favor the products.

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Among the given bases, [tex]NaNH_2[/tex] (sodium amide) and [tex]NaCH_2(CO)N(CH_3)_2[/tex] (sodium diisopropylamide or LDA) are strong enough to deprotonate (propyne) and favor the products.

To determine which bases are strong enough to deprotonate propyne ([tex]CH_3CH_2CH_2C \equiv CH[/tex]), we need to compare their basicity or ability to accept a proton ([tex]H^+[/tex]). The stronger the base, the more likely it is to deprotonate the compound and shift the equilibrium towards the products.

Sodium amide ([tex]NaNH_2[/tex]) and sodium diisopropylamide [tex]NaCH_2(CO)N(CH_3)_2[/tex] ( or LDA) are strong bases commonly used in organic chemistry. They are capable of deprotonating alkynes such as propyne. On the other hand, NaC≡N (sodium cyanide), NaOH (sodium hydroxide), and C6H5Li (phenyllithium) are not strong enough to deprotonate propyne.

Overall, only [tex]NaNH_2[/tex] and [tex]NaCH_2(CO)N(CH_3)_2[/tex] are strong bases that can deprotonate propyne and favor the products.

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On a cold winter day, the temperature is −15 ∘
F. What is that temperature in degrees Celsius?

Answers

To convert -15 ∘ F to degrees Celsius, subtract 32 from -15 ∘ F to get -47 ∘, then divide -47 ∘ by 1.8 to get -26.1 ∘ C. Therefore, the temperature is -26.1 ∘ C.

On a cold winter day, the temperature is −15 ∘ F. To convert this temperature to degrees Celsius, you can use the following
Step 1: Begin with the given temperature in Fahrenheit, which is -15 ∘ F.

Step 2: Subtract 32 from the Fahrenheit temperature to get the difference, which is -15 ∘ F - 32 = -47 ∘.

Step 3: Divide the difference by 1.8 to convert it to degrees Celsius. -47 ∘ / 1.8 = -26.1 ∘ C.

The temperature is -26.1 ∘ C, obtained by subtracting 32 from -15 ∘ F and dividing the result by 1.8.

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Describe how to prepare 500 ml of 6.2 M Na2SO4 (mw 142.0g)

Answers

Dissolve 439.2 grams of Na2SO4 in water while stirring until completely dissolved. Adjust the final volume to 500 ml by adding water gradually.

To prepare 500 ml of a 6.2 M Na2SO4 solution, you would need to start with dissolving and follow these steps:

Step 1: Calculate the amount of Na2SO4 needed:

The molecular weight (MW) of Na2SO4 is 142.0 g/mol. To prepare a 6.2 M solution, you need to determine the number of moles of Na2SO4 required.

Moles = Molarity × Volume (in liters)

Moles = 6.2 mol/L × 0.5 L (500 ml = 0.5 L)

Moles = 3.1 moles

Step 2: Calculate the mass of Na2SO4 needed:

Mass (in grams) = Moles × Molecular Weight

Mass = 3.1 mol × 142.0 g/mol

Mass = 439.2 grams

Therefore, you would need 439.2 grams of Na2SO4 to prepare 500 ml of a 6.2 M solution.

Step 3: Dissolve Na2SO4 in water:

Add a sufficient amount of water to a suitable container or volumetric flask. Slowly add the calculated mass of Na2SO4 (439.2 grams) to the water while stirring continuously until it is completely dissolved.

Step 4: Adjust the final volume:

After the Na2SO4 is dissolved, add water gradually while stirring until the total volume reaches 500 ml. Ensure thorough mixing to obtain a homogenous solution.

Step 5: Verification:

Double-check the concentration by using a reliable analytical technique or pH meter, if available, to confirm that the final solution is indeed 6.2 M Na2SO4.

Remember to handle chemicals with care, wear appropriate personal protective equipment, and follow any safety protocols or guidelines provided by your institution or workplace.

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Consider the following reaction: I−+NO2​−→I2​+NO What is the oxidation state of I in I2​ +1 +2 −1 

Answers

Consider the following reaction I⁻ + NO₂⁻ → I₂ + NO the oxidation state of I in I₂ is +1.

In the given reaction, I₂ is formed as a product. The chemical formula I₂ indicates that each iodine atom has an oxidation state of 0. Since I₂ is a neutral molecule, the sum of the oxidation states of the iodine atoms must be zero.

In the reaction, I⁻ (iodide ion) is one of the reactants. The oxidation state of I in I⁻ is -1 because ions of Group 17 elements (halogens) typically have an oxidation state of -1.

Since I₂ is formed from I⁻, there is a change in the oxidation state of iodine from -1 to 0. Therefore, each iodine atom in I₂ gains one electron, resulting in an oxidation state of +1.

Hence, in I₂, the oxidation state of I is +1.

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2. What other factor would affect the rate of a reaction for the Habe Bosch process? ii) Explain how this factor effects reaction rate.

Answers

Increasing the concentration of reactants in the Haber-Bosch process enhances the reaction rate by increasing the frequency of collisions between the reactant molecules.

The Haber-Bosch process is a well-known industrial process for the production of ammonia (NH3) from nitrogen (N2) and hydrogen (H2).

Besides temperature and pressure, which are the primary factors affecting the rate of the reaction, there are several other factors that can influence the reaction rate in the Haber-Bosch process. One of these factors is the concentration of reactants.

The concentration of reactants refers to the amount of nitrogen and hydrogen present in the reaction mixture. Increasing the concentration of reactants typically leads to an increase in the rate of the reaction.

This is because a higher concentration of reactant molecules increases the frequency of collisions between the reactant particles, which is necessary for a successful reaction to occur.

In the Haber-Bosch process, both nitrogen gas and hydrogen gas are fed into the reactor. By increasing the concentration of these gases, the number of collisions between the reactant molecules is increased.

This, in turn, increases the chances of successful collisions and the formation of ammonia molecules.

Furthermore, increasing the reactant concentration also affects the equilibrium position of the reaction. According to Le Chatelier's principle, if the concentration of reactants is increased, the equilibrium will shift in the direction that consumes the excess reactants.

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q2 Explain the following
diagenesis process and it is affects on permeability and
porosity.
c) replacment /
recrystallization (marks)

Answers

The diagenesis process, specifically replacement/recrystallization, refers to the transformation of minerals within sedimentary rocks through the dissolution of original minerals and subsequent precipitation of new minerals in their place.

During replacement/recrystallization, the original minerals in the rock are dissolved and replaced by new minerals. This can occur due to various chemical reactions, such as the introduction of fluids rich in dissolved ions or changes in temperature and pressure.

The dissolved ions in the fluid can precipitate and form new mineral crystals, effectively replacing the original minerals.

The impact of replacement/recrystallization on permeability and porosity depends on the characteristics of the new minerals formed. If the new minerals have a more compact or tightly packed crystal structure compared to the original minerals, they can reduce the pore space and decrease both permeability and porosity.

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A chemistry graduate student is given 250. ml. of a 1.70M pyridine (C,H,N) solution. Pyridine is a weak base with K-1.7 x 10. What mass of C₂H₁NHBr should the student dissolve in the C3H₂N solution to turn it into a buffer with pH -5.40? You may assume that the volume of the solution doesn't change when the C,H, NHBr is dissolved in 2 significant digits. A Be sure your answer has a unit symbol, and round it to

Answers

The mass of pyridinium hydrobromide required is 15.2 g.

To turn a given pyridine solution into a buffer with pH -5.40, we can use the Henderson-Hasselbalch equation. The Henderson-Hasselbalch equation is a relationship between the pH of a buffer solution and the pKa of the acid-base system, which is given as follows:

Henderson-Hasselbalch equation:

[tex]��=���+log⁡(�−��)pH=pKa+log( HAA − ​ )[/tex]

Here, the pyridine acts as the base (B) and pyridinium hydrobromide (C5H5NHBr) as the acid (BH+) in the buffer. The pKa value for pyridine is given as 5.23. The buffer pH is -5.40, which means the [H+] concentration is 2.5 × 10-6 M (pH = -log[H+]).

[tex]2.5×10−6=�a×[�][��+][/tex]

[tex]⟹  [��+][�]=[�+]�a=109.172.5×10 −6 = [BH + ]K a​ ×[B]​ ⟹ [B][BH + ]​ = K a​ [H + ]​ =10 9.17[/tex]

This gives us the ratio of BH+ to B that we need. To calculate the required mass of pyridinium hydrobromide (BH+), we can use the following equation:

[tex]�=�×�×��m=M×V× Nn[/tex]

where m is the mass of the compound, M is the molecular weight, V is the volume of the solution, n is the number of moles of the compound, and N is the number of moles per liter of the solution.

To calculate the number of moles required, we can use the equation:

[tex][��+][�]=���+��[B][BH + ]​ = n B​ n BH +[/tex]

We know that the volume of the solution is 250 mL, and the concentration of pyridine is 1.70 M.

[tex]��=���[/tex]

[tex]=1.70 M×0.250 L=0.425n B​ =C B​ ×V=1.70 M×0.250 L=0.425 moles of B.[/tex]

Using the ratio calculated earlier, we can find the number of moles of BH+ required:

[tex]���+=[��+][�]×��=109.17×0.425=3.77n BH + ​ = [B][BH + ]​ ×n B​ =10 9.17 ×0.425=3.77 moles of BH+.[/tex]

The molecular weight of pyridinium hydrobromide (BH+) can be calculated as follows:

Molecular weight of BH+ = Molecular weight of C5H5N + Molecular weight of HBr = 79.07 g/mol + 80.91 g/mol = 160.98 g/mol.

Now, we can calculate the mass of BH+ required using the above equation:

[tex]���+=���+����+�[/tex]

=

[tex]160.98 g/mol×0.250 L×3.77 mol1 L=15.2 gm BH + ​ =M BH + ​ ×V× Nn BH + ​ ​ =160.98 g/mol×0.250 L× 1 L3.77 mol​ = 15.2 g[/tex]

Thus, the mass of pyridinium hydrobromide required is 15.2 g.

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a chemist has acid solutions with concentrations 8% and 14%. he wants to mix some of each solution to get 87 milliliters of solution with a 12% concentration. how many milliliters of each solution does he need to mix together?

Answers

The chemist needs to mix 29 milliliters of the 8% acid solution with 58 milliliters of the 14% acid solution to obtain 87 milliliters of a 12% acid solution.

Let's assume the chemist needs to mix x milliliters of the 8% acid solution and y milliliters of the 14% acid solution to obtain a total volume of 87 milliliters with a 12% concentration.

To solve this problem, we can set up a system of equations based on the amount of acid in each solution.

Equation 1: The total volume equation

x + y = 87 ---(1)

Equation 2: The concentration equation

0.08x + 0.14y = 0.12 × 87 ---(2)

Let's solve this system of equations to find the values of x and y.

From equation (1), we can rewrite it as x = 87 - y and substitute it into equation (2):

0.08(87 - y) + 0.14y = 10.44

Simplifying the equation:

6.96 - 0.08y + 0.14y = 10.44

0.06y = 3.48

y = 3.48 / 0.06

y = 58

Now, substitute the value of y back into equation (1) to find x:

x + 58 = 87

x = 87 - 58

x = 29

Therefore, the chemist needs to mix 29 milliliters of the 8% acid solution with 58 milliliters of the 14% acid solution to obtain 87 milliliters of a 12% acid solution.

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Other Questions
Test the series for convergence or divergence using the Alternating Series Test. n=1[infinity](1) n+16ne nIdentify b n Evaluate the following limit. lim n[infinity]b nSince lim n[infinity]b n0 and b n+1b nfor all n, 3NaOH(aq) +K3PO4 (aq) no change yes 9. 2NaOH(aq)+K2CO3(aq) no change 10. 2NaOH(aq) + HSO4(aq) no visable change, no test tube got warm AgNO3(aq) + HCl(aq) white ppt BAgNO3(aq)+3PO4(a)tan ppt 11. 8. 13. 2 AgNO3(aq) +K2CO3 white ppt 14./2CH3COOH(aq)+K Calgas bubbles yes yes yes yes Note: Write molecular, total ionic, and net ionic equations for the above reactions on separate sheets of paper and turn those in with your data sheets. You will receive a zero for Experiment 10 if you do not include the pages with the equations written out. 107 As the instructions on the data sheet indicate, on separate pages (probably two or three) you need to write the molecular, total ionic, and net ionic equations for all the reactions that occurred. Make sure to include physical states and balance the equations appropriately. If no reaction occurs for a particular combination, you still need to indicate the formulas and states of the reactants. However, in these cases the reaction arrow will be followed by "N.R." If no reaction occurs, you do not need to balance the equation for that reaction or write anything for the total ionic or net ionic equations. What can be determined from the table? Check all that apply.The independent variable is the number of gallons.Liters is a function of Gallons.The equation l = 3.79g represents the table.As the number of gallons increases, the number of liters increases. This is a function because every input has exactly one output. Kaarin included statistical information she found on the Food and Drug Administration website in her report. These statistics are a type of Multiple Choice O secondary data. primary data. qualitative information. descriptive analysis. prescriptive analysis. 0 the class was asked to give examples of nutrient-dense foods. which food(s) is considered nutrient dense? select all that apply. Take 2 countries, A and B, both have the following aggregate production function Y=zK 1/2L 1/2.T 1is implies that the per worker production function is given by y=2k 1/2. Assume that for each country %5 of capital depreciates each year. Also, assume that both countries save \%10 of output each year. Assume that country A starts with is level of capital equals to 4(kA=4) while country starts with a level of capital equals to 1(k3=1). Arsume =1. (a) Find the second period's level of cepital for each country (k 2,k 2H). (b) Using the capital levels for periods 1 and 1 , find output for period 1 and period 2. (c) Which country experiences a higher growth rate in output, the one with higher output or lower output per worker? A 15 foot chain hangs from a winch 15 feet above ground level. A bucket of water lies attached to the other end of the chain. The winch begins to wind up the chain. Once the bucket leaves the ground it begins to leak water at a constant rate. Assume that the water bucket weighs 20pounds in the beginning and only 5 pounds once it reaches the winch. Also assume that the chain has a linear density of 3 pounds per foot. Find the work done by the winch during this process. Answer in asked for in nmJsing appropriate data in Table 3.1, compute the interplanar spacing for the (110) set of planes for lead. \( { }^{a} \mathrm{FCC}= \) face-centered cubic; \( \mathrm{HCP}= \) hexagonal close-packed; For the given value of n, use sig In write the left, right, and midpoint Riemann sums. Then evaluate each sum using a calculato f(x)=cos2x for [0, 6];n=60 a. Write the left Riemann sum. k=160360cos( 180k 180) (Type an exact answer, using as needed.) The approximation of the left Riemann sum is (Do not round until the final answer. Then round to three decimal places as needed Determine if the following is solved using a Permutation formula or Combination formula and solve the problem:There are 12 different flavors of Ice creams.a) How many different kinds of bowls of ice cream can be made using 5 different flavors?b) How many 3-scoop cones are possible with each scoop being of a different flavor?c) How many ways can only 4 flavors of ice cream be chosen from the collection? 18. In what section of the statement of cash flows is the repayment of bonds payable reported? Multiple Choice O a. Financing Activities O b. Operating ActivitiesO c. Noncash activities note O d. Investing Activities The air pressure is height-dependent, and the rate of its change with depth is proportional to the air pressure. At the sea level (h = 0), the air pressure is 100 kPa. At a height of 18000 ft, it is 50 kPa. a (a) Please obtain a solution to determine the air pressure distribution along the height. In your answer, please use the following symbols: air pressure p, height h. (6 marks) (b) Please calculate the air pressure at a height of 36000 ft. Flow is delivered from a splitter box to an areation basin through a 12-in. Ductile iron pipe. For a flow rate of 3MGD, the velocity head 9(ft) in the in the ductile iron pipe is a) 0.03 b) 0.54 c) 5.91 d) 59.1 A town has population 475 people at year t=0. Write a formula for the population, P, in year t if the town (a) Grows by 65 people per year: P= (b) Grows by 7% per year: P= (c) Grows at a continuous rate of 7% per year: P= (d) Shrinks by 20 people per year: P= (e) Shrinks by 4% per year: P= (f) Shrinks at a continuous rate of 4% per year: P= 4 cm3 of N2 react with 2 cm3 of O2 to form 4 cm3 of NxOy. Find the chemical formula of NxOy. Which statement best paraphrases the excerpt?Wilma Mankiller says that the Cherokee Nation had treaties with England even before it had treaties with the colonies and the United States government.Wilma Mankiller reminds people that the Cherokee Nation had its own government that signed treaties with other nations before the United States existed.Wilma Mankiller suggests that a nation must have signed treaties in order to be able to govern itself and be recognized by others, which the Cherokee Nation did.The Cherokee Nation has a government that is older than the government of the United States, and was involved in treaties with another country before having treaties with the US. In DNA, an "A" nucleotide is always bonded to a and a " G " is always bonded to a The bonding of A-T involve bonds and the bonding of GC involve bonds Calculate osmotic pressure for a solution containing a nonelectrolyte. The nonvolatile, nonelectrolyte estrogen (estradiol), C 18H 24O 2(272.4 g/mol), is soluble in ethanol, CH 3CH 2OH Calculate the osmotic pressure (in atm) generated when 12.9 grams of estrogen are dissolved in 176 mL of a ethanol solution at 298 K. Determine the molar mass of a solute from osmotic pressure. In a laboratory experiment, a student found that a 124-mL aqueous solution containing 2.767 g of a compound had an osmotic pressure of 33.0 mmHg at 298 K. The compound was also found to be nonvolatile and a nonelectrolyte. What is the molar mass of this compound? At the beginning of the twentieth century, the force of nationalism had led many European groups who were part of larger state or imperial structures to insist on their right to national self-determination. In what ways did the idea of tradition inform and justify their various calls for separate nationhood? Find all values ofand all values ofin[0,2]for the equation given below. Be sure to the algebra or trigonometry you use and give exact values to ensure full credit.sin(3x)=3/2