Use the formation reactions below such that when added together, they match the balanced equation for the combustion of methane.
Cgraphite(s)+ 2H2(g) → CH4(g) ΔH 1=−74.80kJ
Cgraphite(s)+ O2(g) → CO2(g) ΔH2=−393.5k
H2(g)+ 1/2O2(g) → H2O(g) ΔH3=−241.80kJ
Calculate ΔHrxn for the combustion of methane, CH4(g).
CH4(g)+ 2O2(g) → CO2(g)+ 2H2O(g) ΔHrxn =--------------kJ

Answer:

The information has been changed to support a claim

Explanation:

Answer: The equation for the reaction that goes with this equilibrium constant is [tex]5.56\times 10^{-10}=\frac{[CH_3COOH]}{[CH_3COO^-]\times [H^+]}[/tex]

Explanation:

[tex]CH_3COOH\rightarrow CH_3COO^-+H^+[/tex]

Here [tex]CH_3COOH[/tex] donates a proton and thus behaves as an acid and forms [tex]CH_3COO^-[/tex] which is called as the conjugate base of [tex]CH_3COOH[/tex]

The dissociation constant of acids is given by the term [tex]K_a[/tex] and the dissociation constant of bases is given by the term [tex]K_b[/tex] and is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios.

[tex]K_a[/tex] for  [tex]CH_3COOH[/tex] :

[tex]K_a=\frac{[CH_3COO^-]\times [H^+]}{[CH_3COOH]}[/tex]

[tex]CH_3COO^-+H^+\rightarrow CH_3COOH[/tex]

[tex]K_b=\frac{[CH_3COOH]}{[CH_3COO^-]\times [H^+]}[/tex]

[tex]5.56\times 10^{-10}=\frac{[CH_3COOH]}{[CH_3COO^-]\times [H^+]}[/tex]

The equation for the reaction that goes with this equilibrium constant is [tex]K_b=\frac{[CH_3COOH]}{[CH_3COO^-]\times [H^+]}[/tex]

Answer: the exciation of molecules is brount by absorption of energy  in spectroscpy

Explanation:

42.1°C is the final temperature when a 25.0 g block of aluminum (initially at 25 °C) absorbs 10.0 kJ of heat.

The physical concept of temperature indicates in numerical form how hot or cold something is. A thermometer is used to determine temperature. Thermometers are calibrated using a variety of temperature scales, which historically defined distinct reference points or thermometric substances.

The most popular scales include the Celsius scale, sometimes known as centigrade, with the unit symbol °C, the scale of degrees Fahrenheit (°F), or the Kelvin scale (K), with the latter being mostly used for scientific purposes. One of the United Nations System of Units' (SI) seven base units is the kelvin.

Q=725 J

m=55.0 g

c=0.900 J/(°C⋅g)

ΔT=final temperature - initial temperature

ΔT=(x−27.5)°C

725 J=55.0 g⋅0.900 J/(°C⋅g)(x−27.5)

X=42.1°C

Therefore, 42.1°C is the final temperature when a 25.0 g block of aluminum (initially at 25 °C) absorbs 10.0 kJ of heat.

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Answer:

Molar mass = 71.76 g/mol

Explanation:

The relationship between molar mass and rate of effusion is given as;

Vh / Vu = √ (Mu / Mh)

The rate of effusion of a gas is inversely proportional to the square root of the mass of its particles.

Rate = volume /  time (Assuming Volume = 1)

Vh = Rate of effusion of Hydrogen = 1 / 2.42

Vu = Rate of effusion of unknown gas = 1 / 14.5

Mh = Molar mass of hydrogen = 2

Mu = Molar mass of unknown gas = x

Substituting into the formular, we have;

(1 / 2.42) / (1 / 14.5) = √ ( x / 2)

5.99 = √ ( x / 2)

35.88 = x / 2

x = 71.76

Answer:

2.8 times 10^ -2

Explanation:

scientific notation is supposed to be a number between 1 and 10

the decimal point moves 2 to the right in order to get 2.8 which makes the exponent negative

Complete Question

The complete question is shown on the first uploaded image

Answer:

For reaction 1

    [tex]K_{eq} = 10^{29}[/tex]

     The equilibrium position is to the right

For reaction 2

        The equilibrium position is to the left

Explanation:

Generally  [tex]pKa[/tex] is mathematically evaluated as  

[tex]pKa = pKa _ \ {left }} - pKa _ \ {right }}[/tex]

And equilibrium position [tex]K_a[/tex] is mathematically evaluated as [tex]K_{eq} = 10^\ {-pK_a}[/tex]

From the question we are told that

For reaction 1

         [tex]pKa_\ {left}} \ = 9[/tex]

        [tex]pKa_\ {right }} \ = 38[/tex]

So

       [tex]pKa = 9-38[/tex]

       [tex]pKa =-29[/tex]

So  [tex]K_{eq} = 10^{-(-29)}[/tex]

      [tex]K_a = 10^{29}[/tex]

This implies that the equilibrium position is to the right

   For reaction 2

       [tex]pKa_\ {left}} \ = 15.9[/tex]

       [tex]pKa_\ {right }} \ = 9.24[/tex]

So

       [tex]pKa = 15.9-9.24[/tex]

       [tex]pKa = 6.66[/tex]

So  [tex]K_{eq} = 10^{-(6.66)}[/tex]

      [tex]K_{eq} = 10^{-6.66}[/tex]

This implies that the equilibrium position is to the left

Answer:

4.41

Explanation:

Step 1: Write the balanced equation

CO(g) + 3 H₂(g) = CH₄(g) + H₂O(g)

Step 2: Calculate the respective concentrations

[tex][CO]_i = \frac{0.500mol}{5.00L} = 0.100M[/tex]

[tex][H_2]_i = \frac{1.500mol}{5.00L} = 0.300M[/tex]

[tex][H_2O]_{eq} = \frac{0.198mol}{5.00L} = 0.0396M[/tex]

Step 3: Make an ICE chart

        CO(g) + 3 H₂(g) = CH₄(g) + H₂O(g)

I       0.100      0.300        0            0

C         -x           -3x          +x          +x

E    0.100-x    0.300-3x     x            x

Step 4: Find the value of x

Since the concentration at equilibrium of water is 0.0396 M, x = 0.0396

Step 5: Find the concentrations at equilibrium

[CO] = 0.100-x = 0.100-0.0396 = 0.060 M

[H₂] = 0.300-3x = 0.300-3(0.0396) = 0.181 M

[CH₄] = x = 0.0396 M

[H₂O] = x = 0.0396 M

Step 6: Calculate the equilibrium constant (Kc)

[tex]Kc = \frac{[CH_4] \times [H_2O] }{[CO] \times [H_2]^{3} } = \frac{0.0396 \times 0.0396 }{0.060 \times 0.181^{3} } = 4.41[/tex]

Answer:

D) Evaluating it with experimentation and argument.

Explanation:

If you don't have enough observational evidence, then you can't really strengthen your scientific knowledge, because you haven't collected enough information to answer the questions you're asking.

If you only have a few scientists working on a question, it will take longer to find an answer. With more people working on a concept, it can be solved in more time.

It can be good to create new hypotheses, but only if you've already tested your original hypothesis (with experimentation and argument), and it turned out to be wrong. Once you've rejected your first hypothesis, only then should you make a new one.

Answer:

D

Explanation:

Answer:

1.97kJ of energy are released.

Explanation:

The dissolution of LiOH in water is:

LiOH(s) → Li⁺(aq) + OH⁻(aq) ΔH = -23.6kJ

That means, when 1 mole of LiOH is dissolved, there are released (Because of the - in the enthalpy) 23.6kJ

2.0 g of LiOH (Molar mass: 23.95g/mol) are:

2.0g LiOH × (1 mol / 23.95g) =0.0835 moles of LiOH.

As 1 mole of LiOH release 23.6kJ, 0.0835moles release:

0.0835moles × (-23.6kJ / 1mole) = 1.97kJ of energy are released

Answer:

A

Explanation:

They are all found in the reactants side

Answer:

True

Explanation:

Due to the arrangement of the molecule, a carbon dioxide molecule is non-polar.

Answer:

It is called 'solar noon'

Explanation:

It's when the sun is at its highest

And also the moment the sun crosses the meridian.

Answer:

A. Ca(OH)2 ----> CaO + H2O; ∆H = +109KJ

B. Check attached document below for the enthalpy diagram

Explanation:

A thermochemical equation is a balanced chemical equation in which enthalpy change is variable. It tells about the nature of the reaction.

Enthalpy change is the difference between the heat content of the products and reactants in a thermochemical equation.

∆H is negative for an exothermic reaction (a reaction where heat is given out), while it is positive for an endothermic reaction ( a reaction in which heat is added).

The activation energy, Ea, is the minimum amount of energy reactant particles must possess in order for a reaction to proceed towards product formation.

As per the decomposition of the Ca(OH) 2 and the CaO the constant pressure needs to be added of the 109KJ.

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Answer:

I. Lewis acid-base reaction

II. Arrhenius, Brønsted-Lowry, and Lewis' acid-base reaction

III. Brønsted-Lowry and Lewis'acid-base reaction

IV. Lewis acid-base reaction

Explanation:

According to Arrhenius, an acid is a substance that dissolves in water to produce H+ ions, and a base is a substance that dissolves in water to produce hydroxide (OH−) ions.

In the reaction below, AH is an avid, BOH is a base reacting together to form a salt(A-B+) and water only.

AH + BOH ---> A-B+ + H2O

According to Brønsted-Lowry definition, an acid is any substance that can donate a proton, and a base is any substance that can accept a proton.

In the reaction below, AH is an acid while B is a base, reacting together to form an acid-base conjugate pair.

AH + B <-----> BH+ + A-

According to Lewis' definition, an acid is a species that accepts an electron pair while a base donates an electron pair resulting in a coordinate covalently bonded compound, also known as an adduct. In the reaction below, A+ is an acid, B- is a base, reacting together to form product A-B.

A+ + B- ------> A-B

Considering the above definitions;

I. Cu²+ + 4 Cl− ---> CuCl4²− is a Lewis acid-base reaction because it involves electron sharing only.

II. Al(OH)3 + 3HNO3 ---> Al3+ + 3H2O + 3 NO3− is an Arrhenius, Brønsted-Lowry, and a Lewis acid-base reaction because it involves protons, electrons and hydroxide ions.

III. N2 + 3 H2 ---> 2NH3 is a Lewis acid-base reaction because it involves sharing of electrons only.

IV. CN− + H2O ---> HCN + OH is both a Lewis and Brønsted-Lowry acid-base reaction because both protons and electrons sharing is involved.

In a Bronsted-Lowry acid-base reaction reaction, an acid donates protons which is accepted by the base.

The following are useful definitions of acids and bases;

Based on these, we can now classify the reactions accordingly;

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Answer:

Aspirin is usually packaged with C. buffering agents.

Explanation:

Answer:

−153.1 J / (K mol)

Explanation:

Calculate the standard entropy of reaction at 298 K for the reaction Hg(liq) + Cl2(g) → HgCl2(s) The standard molar entropies of the species at that temperature are: Sºm (Hg,liq) = 76.02 J / (K mol) ; Sºm (Cl2,g) = 223.07 J / (K mol) ; Sºm (HgCl2,s) = 146.0 J / (K mol)

Hg(liq) + Cl2(g) → HgCl2(s)

Given that;

The standard molar entropies of the species at that temperature are:

Sºm (Hg,liq) = 76.02 J / (K mol) ;

Sºm (Cl2,g) = 223.07 J / (K mol) ;

Sºm (HgCl2,s) = 146.0 J / (K mol)

The standard molar entropies of reaction = Sºm[products] - Sºm [ reactants]

= 146.0 J / (K mol) – [76.02 J / (K mol) +223.07 J / (K mol) ]

= -153.09 J / (K mol)

= or -153.1 J / (K mol)

Hence the answer is  −153.1 J / (K mol)

Answer:

Solubility cannot be calculated.

Explanation:

To calculate the solubility of X it is necessary to know the value of the mass of the solute (X) that can be dissolved in 100 g of water.

[tex]Solubility = \frac{Solute mass}{100 grams of water}[/tex]

Taking into account that we do not know the value of the mass of the solution, therefore the value of the solubility of the compound cannot be determined.

Answer:

C3H6O

Explanation:

Step 1:

Data obtained from the question include the following:

Mass of the compound = 0.225g

Mass of CO2 = 0.512g

Mass of H2O = 0.209g

Step 2:

Determination of the masses of carbon, hydrogen and oxygen present in the compound.

This is illustrated below:

For Carbon, C:

Molar mass of CO2 = 12 + (2x16) = 44g/mol

Mass of C in CO2 = 12/44 x 0.512 = 0.1396g

For Hydrogen, H:

Molar mass of H2O = (2x1) + 16 = 18g/mol

Mass of H in H2O = 2/18 x 0.209 = 0.0232g

For Oxygen, O:

Mass of O = 0.225 – (0.1396 + 0.0232)

Mass of O = 0.0622g

Step 3:

Determination of the empirical formula for caprioc acid.

This can be obtain as follow:

C = 0.1396g

H = 0.0232g

O = 0.0622g

Divide by their molar mass

C = 0.1396/12 = 0.0116

H = 0.0232/1 = 0.0232

O = 0.0622/16 = 0.0039

Divide by the smallest

C = 0.0116/0.0039 = 3

H = 0.0232/0.0039 = 6

O = 0.0039/0.0039 = 1

Therefore, the empirical formula for caprioc acid is C3H6O

Answer:

30 mL VOLUME OF 3.0 M HCl SHOULD BE USED BY THE STUDENT TO MAKE A 1.80 M IN 50 mL OF HCl.

Explanation:

M1 = 3.00 M

M2 = 1.80 M

V2 = 50 .0 mL = 50 /1000 L = 0.05 L

V1 = unknown

In solving this question, we know that number of moles of a solution is equal to the molar concentration multiplied by the volume. To compare two samples, we equate both number of moles and substitute for the required component.

So we use the equation:

                                  M1 V1 = M2 V2

V1 = M2 V2 / M1

V2 = 1.80 * 0.05 / 3.0

V2 = 0.09 /3.0

V2 = 0.03 L or 30 mL

To prepare the sample of 1.80 M HCl in 50.0 mL from a 3.0 M HCl, 30 mL volume should be used.

Answer:

Explanation:

i dont like reading

Answer:

The correct answer to the question is Option E (Strongly retained analytes will give broad peaks).

Explanation:

The other options are true because:

A. Initial temp = 50 °C

   Final temp =  270 °C

Differences in temp = 270 - 50 = 220°C

Rate =  10 °C/minute.

So, at 10 °C/minute,

total of 220°C /10 °C = number of minutes required to reach the final temp.

220/10 = 22 minutes

B. A column has a minimum and maximum use temperature. Solutes that are already retained would remain stationary while temperatures are low. This would only change if there is an increase in temperature. Heat transfers more energy to the liquid which would make the solute interact with the column phase.

C. Weakly retained solutes may contain larger molecules, will separate by absorbing into the solvent early in separation making the mobile phase separates out into its components on the stationary phase.

D. Retained solute's vapor pressure is higher at higher temperatures making it possible for particle to escape more from the solute when the temperature is high than when it is low.

Answer:

218.3 g/mol

Explanation:

Boiling point elevation occurs when a solute is added to a solvent increasing the boiling point of the solution with regard to the pure solvent.

The law is:

ΔT = Kb×m×i

Where ΔT is change in temperature (3.67°C), Kb is the boiling point constant of the solvent (4.95°C/m), m is molality of the solution and i is Van't Hoff factor (1 for a non-electrolyte).

3.67°C = 4.95°C/m×m×i

0.7414m = molality of the solution (Moles solute / kg solvent).

As the mass of the solvent is 50.0g = 0.0500kg:

0.7414m = Moles solute / 0.0500kg

0.0371 = moles of solute

As the mass of the solute is 8.1g, molar mass of the solute (Ratio between mass in g and moles) is:

8.1g / 0.0371mol =

Answer:

a physical change is something that has not been modified chemically and can possibly be changed back to the state it was once before. A physical change keeps all the same atoms and none of them is modified.

Example:

When a block of clay is morphed into a giraffe statue, it can be morphed back to its original state. If someone burnt the block of clay, the atoms would be modified and it would be unable to go back to its previous state.

-----------------------------------------------------------------------------------------------------------------

(If you're referring to a question with these answers)

A. iron rusting

B. milk turning to curd

C. water boiling

D. paper burning

E. hard water staining pipes

-----------------------------------------------------------------------------------------------------------------

Answer:

C. Water Boiling

(If you are referring to a question with these answers I think this is the correct answer if not I do apologize)

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Answer:

Explanation:

Calcium oxide is fromed by the decomopostion of CaCO3 at high temperature.

CaCO3   ------> CaO  +CO2

Hope this helps you

Answer:

True

Explanation:

A real image can be projected or seen on a screen but a virtual image cannot because a real image is formed when light rays coming from an object actually meet at a point after refraction through a lens while a virtual image is formed when light rays coming from an object only appear to meet at a point when produced ...

Hope this helps you, and Good luck!

Answer:

43.45g of water would be produced from the reaction.

Explanation:

Liquid became reacts with oxygen to produce carbon dioxide and water.

This type of reaction is known as combustion reaction between alkanes.

Equation of reaction.

Assuming the reaction occurs in an unlimited supply of oxygen,

2C₆H₁₄ + 19O₂ → 12CO₂ + 14H₂O

From the above equation of reaction,

2 moles of C₆H₁₄ reacts with 19 moles of O₂ to produce 14 moles of H₂O.

To find the theoretical mass,

Number of moles = mass / molar mass

Molar mass of C₆H₁₄ = 86g/mol

Molar mass of O₂ = 16g/mol × 2 = 32g/mol

Molar mass of H₂O = 18g/mol

Mass of H₂O = number of moles × molar mass

Mass of H₂O = 14 × 18 = 252g

Mass of C₆H₁₄ = number of moles × molar mass

Mass of C₆H₁₄ = 2 × 86 = 172g

Mass of O₂ = number of moles × molar mass

Mass of O₂ = 19 × 32 = 608g

From the equation of reaction,

172g of C₆H₁₄ reacts with 608g of O₂ to produce 252g of H₂O

(172 + 608)g of reactants produce 252g of H₂O

780g of reactants produce 252g of H₂O

(60 + 75.5)g of reactants will produce a x g of H₂O

780g of reactants = 252g of H₂O

134.5g of reactants = x g of H₂O

X = (134.5 × 252) / 780

X = 43.45g of H₂O

Therefore, 43.45g of H₂O would be produced from 60g of hexane and 74.5g of oxygen

Answer:

[tex]m_{H_2O}=30.9gH_2O[/tex]

Explanation:

Hello,

In this case, the combustion of hexane is given by:

[tex]C_6H_{14}+\frac{19}{2} O_2\rightarrow 6CO_2+7H_2O[/tex]

The next step is to compute the reacting moles of hexane:

[tex]n_{C_6H_{14}}=60gC_6H_{14}*\frac{1molC_6H_{14}}{86gC_6H_{14}} =0.698molC_6H_{14}[/tex]

Then, the moles of hexane consumed by 74.5 g of oxygen using the molar ratio in the chemical reaction (1:19/2):

[tex]n_{C_6H_{14}}=74.5gO_2*\frac{1molO_2}{32gO_2} *\frac{1molC_6H_{14}}{19/2molO_2} =0.245molC_6H_{14}[/tex]

Therefore, as less moles of hexane are consumed by oxygen, it is in excess, so we compute the mass of water produced by the consumed 0.245 moles of hexane:

[tex]m_{H_2O}=0.245molC_6H_{14}*\frac{7molH_2O}{1molC_6H_{14}}*\frac{18gH_2O}{1molH_2O} \\\\m_{H_2O}=30.9gH_2O[/tex]

Best regards.

Answer:

Li>Na>K>Rb

Explanation:

Answer:

c. Li > Na > K > Rb

Explanation:

edge 2021

(:

Answer:

B and D

Explanation:

If we use the info given we have a band a 3300 cm-1 and 2200 cm-1 this indicates that we have an alkyne functional group. Additionally, the hydrogenation of the unknown molecule will consume two moles of hydrogens this fits with the 2 pi bonds in the alkyne functional group. So, we can discard "a" and "e". The product of this hydrogenation is 2-methylhexane therefore we can discard c because the methyl group is placed on carbon 3. Structures b and d can work.

See figure 1

I hope it helps!

Answer:

polyethylenes

Explanation:

the plastic bottles used to hold potable water and other drinks are made from polyethylene because, the material is both strong and light.

hope this helped!

Answer: Polyethylenes

Explanation: I got 100% on the test :)

Answer:

im pretty sure its 2.54g H2

Explanation:

14.34gNH3 / 17.03gNH3 <-- molar mass

.842g x 3 mol <-- mols of H2

2.52 / 2 mol <-- mols of NH3

1.26 x 2.016gH2= 2.54gH2