The half-life of radium-226 is 1590 years. (a) A sample of radium-226 has a mass of 50 mg. Find a formula for the mass of the sample that remains after t years. (b) Find the mass after 500 years correct to the nearest milligram. (c) When will the mass be reduced to 40 mg

Answers

Answer 1

Answer:

Explanation:

a )

m = m₀ [tex]e^{-\lambda t[/tex]

m is mass after time t . original mass is m₀ , λ is disintegration constant

λ = .693 / half life

= .693 / 1590

= .0004358

m = m₀ [tex]e^{- 0.0004358 t}[/tex]

b )

m = 50 x [tex]e^{-.0004358\times 500}[/tex]

= 40.21 mg .

c )

40 = 50 [tex]e^{-.0004358t[/tex]

.8 = [tex]e^{-.0004358t[/tex]

[tex]e^{.0004358t[/tex] = 1.25

.0004358 t = .22314

t = 512 years .


Related Questions

A chemist titrates of a butanoic acid solution with solution at . Calculate the pH at equivalence. The of butanoic acid is__________ .Round your answer to decimal places.
Note for advanced students: you may assume the total volume of the solution equals the initial volume plus the volume of solution added.

Answers

Answer:

pH = 8.75

Explanation:

100.0mL of a 0.8108M of a butanoic acid (HC₃H₇CO₂, pKa 4.82) solution is titrated with 0.0520M KOH.

The reaction is:

HC₃H₇CO₂ + KOH → H₂O + KC₃H₇CO

Moles of butanoic acid are:

0.1000L × (0.8108mol / L) = 0.08108 moles of butanoic

For a complete reaction, volume of KOH must be added is the volume in which 0.08108 moles of KOH are added, that is:

0.08108 mol × (L / 0.0520mol) = 1.56L of KOH.

Total volume in equilibrium is 1.56L + 0.10L = 1.66L

That means concentration of butanoic acid is:

0.08108 mol / 1.66L = 0.04884M HC₃H₇CO₂

At equivalence point, there is just C₃H₇CO⁻ in solution

Kb of butanoic acid is:

C₃H₇CO⁻ + H₂O ⇄ HC₃H₇CO₂ + OH⁻

Kb = Kw / Ka

Ka = 10^-pKa

Ka = 1.51x10⁻⁵

Kb = 1x10⁻¹⁴ / 1.51x10⁻⁵ = 6.61x10⁻¹⁰

The equilibrium of Kb is:

Kb = 6.61x10⁻¹⁰ =  [HC₃H₇CO₂] [OH⁻] / [C₃H₇CO⁻]

As at equivalence point there is just C₃H₇CO⁻, the equilibrium concentrations are:

[C₃H₇CO⁻] = 0.04884M - X

[HC₃H₇CO₂] = X

[OH⁻] = X

Replacing in Kb:

6.61x10⁻¹⁰ =  X² / [0.04884M - X]

0 =  X² + 6.61x10⁻¹⁰X - 3.23x10⁻¹¹

Solving for X:

X = -5.68x10⁻⁶ → False solution. There is no negative concentrations

X = 5.683x10⁻⁶ → Right solution.

As [OH⁻] = X, [OH⁻] = 5.683x10⁻⁶.

pOH = - log [OH⁻]

pOH = 5.245

pH = 14 - pOH

pH = 8.75

At high temperatures one mole of hydrogen gas reacts with one mole of bromine gas to form hydrogen bromide. At a given temperature the equilibrium constant is 57.6. If at the same temperature, a mixture of 4.67 × 10^-3M bromine gas, 2.14 × 10^−3 hydrogen gas, and 2.40 × 10^−2M hydrogen bromide gas is made, then:

a. the system is at equilibrium.
b. the system is far from equilibrium and will shift to form more hydrogen gas.
c. the system is far from equilibrium and will shift to form more hydrogen bromide gas.
d. nothing can be deduced since we do not know whether the reaction is endothermic or exothermic.
e. nothing can be deduced since we do not know whether the equilibrium constant is Kc or Kp.

Answers

Answer:

a. the system is at equilibrium.

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

[tex]H_2+Br_2\rightleftharpoons 2HBr[/tex]

Thus, the law of mass action is given by:

[tex]Keq=\frac{[HBr]^2}{[H_2][Br_2]} =57.6[/tex]

Nonetheless, for the given point of 4.67 × 10^-3M bromine gas, 2.14 × 10^−3 hydrogen gas, and 2.40 × 10^−2M hydrogen bromide gas we should compute the reaction quotient in order to know whether the direction of the reaction is to left or to right, thus:

[tex]Q=\frac{[HBr]^2}{[H_2][Br_2]} =\frac{(2.40x10^{-2})^2}{(4.67x10^{-3})(2.14x10^{-3})} \\\\Q=57.6[/tex]

Therefore, since Keq=Q, we say that the system is at equilibrium, for that reason, the answer is a.

Best regards.

For the iodine trichloride molecule: a. Determine the number of valence electrons for each atom in the molecule b. Draw the Lewis Dot structure c. Describe why the molecule is drawn this way (i.e. any extra rules/steps needed?) d. Show the polarity of each bond and for the molecule by drawing in the dipole +à

Answers

Answer:

Explanation:

a. Determine the number of valence electrons for each atom in the molecule

In this case we both atoms are halogens. Therefore we will have 7 electrons for each atom.

b. Draw the Lewis Dot structure

In this case, the formula is [tex]ICl_3[/tex], so the central atom would be "I" and the "Cl" atoms would be placed around "I". See figure 1

c. Describe why the molecule is drawn this way (i.e. any extra rules/steps needed?)

In this specific case, the "I" atom don't follow the octet rule. We will have an expanded octet for iodine (more than 8 electrons).

d. Show the polarity of each bond and for the molecule by drawing in the dipole +d

The negative dipole would be placed in the atom with higher electronegativity, in this case "Cl". The positive dipole would be placed in the atom with low electronegativity, in this case "I".

I hope it helps!

Consider the following specific heats of metals. Metal Specific Heat Aluminum 0.897 J/(g°C) Magnesium 1.02 J/(g°C) Lithium 3.58 J/(g°C) Silver 0.237 J/(g°C) Gold 0.129 J/(g°C) If the same amount of heat is added to 25.0 g of each of the metals, which are all at the same initial temperature, which metal will have the lowest temperature?

Answers

Answer:

Lithium

Explanation:

The specific geat capacity of a substance is the energy required to raise 1 unit of that substance by one degree.

Heat energy (Q) = mc∇t

Q = heat energy

M = mass of the substance

c = specific heat capacity

∇t = change in temperature of the substance

Generally, increase in the specific heat capacity will lead to a lower final temperature likewise decrease in the specific heat capacity will lead to increase the final temperature of the substance.

From the data above, we can take just two specific heat capacity and test this theory.

Assuming we have a

Mass = 25g

Heat energy applied (Q) = 1 J

Initial temperature (T1) = 10°C

Final temperature (T2) = ?

Q = mc∇t

Q = mc (T2 - T1)

For Lithium, specific heat capacity = 3.58J/g°C

1 = 25 × 3.58 (T2 - 10)

Solve for T2

1 = 89.5 (T2 - 10)

1 = 89.5T2 - 895

89.5T2 = 896

T2 = 896 / 89.5

T2 = 10.011°C

For Magnesium (Mg) specific heat capacity = 1.02J/g°C

Q = mc∇t

1 = 25 × 1.02 × (T2 - 10)

1 = 25.5 (T2 - 10)

1 = 25.5T2 - 255

Solve for T2

25.5T2 = 256

T2 = 10.039°C

Notice the trend that decrease in the specific heat capacity leads to increase in the final temperature.

Try and continue for the elements and see how it works.

What is the temperature at which the substance can be both in the solid and the liquid phase?

Answers

Answer: Gas–liquid–solid triple point

The single combination of pressure and temperature at which liquid water, solid ice, and water vapor can coexist in a stable equilibrium occurs at approximately 273.1575 K (0.0075 °C; 32.0135 °F) and a partial vapor pressure of 611.657 pascals (6.11657 mbar; 0.00603659 atm).

Explanation:

It represents the equilibrium between the liquid and gas phases. The point on this curve where the vapor pressure is 1 atm is the normal boiling point of the substance. The vapor-pressure curve ends at the critical point (B), which is at the critical temperature and critical pressure of the substance.

Which of the following is an example of a mechanical wave?
O A. A light ray
B. A seismic wave
C. A radio wave
D. An X-ray

Answers

Answer:

A seismic wave

Explanation:

It requires a medium for its propagation.

What is Keq for the reaction 2HCl(9) = H2(g) + Cl2(g)?

Answers

Answer:

Keq= [(Cl2) (H2)] / (HCl)^2

Explanation:

Equilibrium Constant, Keq, is written as products/reactants.

So it's going to be Keq= [(Cl2) (H2)] / (HCl)^2

A laser is used in eye surgery to weld a detached retina back into place. The wavelength of the laser beam is 503 nm, while the power is 1.4 W. During surgery, the laser beam is turned on for 0.070 s. During this time, how many photons are emitted by the laser?

Answers

Answer:

Number of proton emmitted by laser=[tex]2.48*10^17proton[/tex]

Explanation:

Energy is the ability to cause change; power is directly proportional to energy and its the rate energy is utilized.

Power=energy/time.

First we need to calculate the total energy used which is equal to the total power utilized.

E(total)= P( total) = 1.4W × 0.070 s =[tex]0.098J[/tex]

CHECK THE ATTACHMENT FOR THE REMAINING DETAILED CALCULATION

The compound ClF contains Group of answer choices polar covalent bonds with partial negative charges on the Cl atoms. ionic bonds. nonpolar covalent bonds. polar covalent bonds with partial negative charges on the F atoms.

Answers

Answer:

polar covalent bonds with partial negative charges on the F atoms.

Explanation:

A covalent bond could be polar or nonpolar depending on the relative electro negativity difference between the two bonding atoms. In this case, the bonding atoms are chlorine and fluorine.

In the Pauling's scale, fluorine has an electro negativity value of 3.98 while chlorine has an electro negativity value of 3.16. The difference in electro negativity between the two atoms is about 0.82. This magnitude of electro negativity difference between the two bonding atoms correspond to the existence of a polar covalent bond in the molecule.

The direction of the dipole depends on the relative electro negativity values of the two bonding atoms. Since fluorine is more electronegative than chlorine, the fluorine atom will be partially negative and the chlorine atom will be partially positive accordingly.

The compound ClF (chlorine monofluoride) contains polar covalent bonds with partial negative charges on the F atoms. Therefore, option D is correct.

In ClF, chlorine (Cl) is more electronegative than fluorine. As a result, the shared electrons in the Cl-F bond are pulled closer to the chlorine atom, creating a partial negative charge on the fluorine atoms and a partial positive charge on the chlorine atom.

This polarity in the Cl-F bond gives the molecule an overall polarity, making it a polar molecule. Thank you for pointing out the error, and I apologize for any confusion caused.

Thus, option D is correct.

To learn more about the polar covalent bonds, follow the link:

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Gravity on Earth is 9.8 m/s2, and gravity on the Moon is 1.6 m/s2.

so if the mass of an object on earth is 40 kilograms what is the mass on the moon.
and how much does it way

Answers

Answer:

Mass is the same but it weights 64 Newtons

Explanation:

First of Mass is the same in any sort of gravity. Now let's calculate weight

W = MG

where W = Weight

M = Mass

G = Gravity

W = (40kg)(1.6)

W = 64

Sorry for the spelling mistakes, hope this helps

Answer:6.61kilo

Explanation: fdfv

One of the reagents below gives predominantly 1,2 addition (direct addition) while the other gives predominantly 1,4 addition (conjugate addition). a) Which major organic product is the result of 1,2 addition? ---Select--- b) Draw the skeletal structure of major organic product A

Answers

Complete Question

The complete question is shown on the first uploaded image

Answer:

a

The correct option is reagent B

b

The  skeletal structure of major organic product A is shown on the third uploaded image

Explanation:

The mechanism of the reaction for A and  B  are shown on the second the second reaction and looking at this we can see that the reagent that  predominately gives 1,2 addition is reagent B  

Catalysts are substances that increase the rate of reaction but can be recovered unchanged at the end of the reaction. Catalysts can be classified as either homogeneous (same state as reactants) or heterogeneous (different state than reactants).
Platinum is used to catalyze the hydrogenation of ethylene:
H2(g)+CH2CH2(g)−⟶Pt(s)CH3CH3(g)
Chlorofluorocarbons (CFCs) catalyze the conversion of ozone (O3) to oxygen gas (O2):
2O3(g)−⟶CFC(g)3O2(g)
Magnesium catalyzes the disproportionation of hydrogen peroxide to produce water and oxygen:
2H2O2(aq)−⟶Mg(s)2H2O(l)+O2(g)
What type of catalysts are platinum, CFCs, and magnesium under these conditions?

Answers

Answer:

-  Platinum acts as a heterogeneous catalyst in the hydrogenation of ethylene.

- CFCs act as homogeneous catalysts in the conversion of ozone to oxygen gas.

- Magnesium acts as a heterogeneous catalyst in the disproportionantion of hydrogen peroxide.

Explanation:

Hello,

For the given reactions, considering the definition of homogeneous and heterogeneous catalyst, we can identify that is each catalyst behave as follows:

-  Platinum acts as a heterogeneous catalyst in the hydrogenation of ethylene as all the reactants are gaseous but it remains solid.

- CFCs act as homogeneous catalysts in the conversion of ozone to oxygen gas as it remains gaseous as well as both ozone and oxygen.

- Magnesium acts as a heterogeneous catalyst in the disproportionantion of hydrogen peroxide as it is solid whereas the other species are aqueous, liquid and gaseous

Best regards.

g Identify the type of reaction [(combination (c), decomposition (d), combustion (co), single replacement (sr), double replacement (dr) , or neutralization (n)] and write a balanced equation. If there is no reaction, write NR. Aqueous ammonium phosphate reacts with aqueous calcium sulfide.

Answers

Answer: [tex]2(NH_4)_3PO_4(aq)+3CaS(aq)\rightarrow Ca_3(PO_4)_2(aq)+3(NH_4)_2S(s)[/tex] is a double displacement reaction (dr).

Explanation:

A double displacement reaction (dr) is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.

[tex]2(NH_4)_3PO_4(aq)+3CaS(aq)\rightarrow Ca_3(PO_4)_2(aq)+3(NH_4)_2S(s)[/tex]

Combination reaction (C) is defined as the reaction where substances combine in their elemental state to form a single compound.

Single displacement reaction (sr) is defined as the reaction where more reactive element displaces a less reactive element from its chemical reaction.

Decomposition reaction (d) is defined as the reaction where a single substance breaks down into two or more simpler substances.

Combustion (Co) is a type of chemical reaction in which hydrocarbons burn in the presence of oxygen to form carbon dioxide and water along with heat.

A thermometer is placed in water in order to measure the water’s temperature. What would cause the liquid in the thermometer to rise? The molecules in the water move closer together. The molecules in the thermometer’s liquid spread apart. The kinetic energy of the water molecules decreases. The kinetic energy of the thermometer’s liquid molecules decreases.

Answers

Answer:

The molecules in the thermometer’s liquid spread apart

Explanation:

The molecules in the thermometer’s liquid spread apart.

What is thermometer?

A thermometer is a device that measures temperature or a temperature gradient.

What causes the liquid in the thermometer to rise?

The liquid (water) in thermometer exhibits convex meniscus, as a result of this meniscus, the water molecules in the thermometer will spread apart when temperature is measured.

Learn more about thermometer here: https://brainly.com/question/21720093

When an unsymmetrical alkene such as propene is treated with N-bromosuccinimide in aqueous dimethyl sulfoxide, the major product has the bromine atom bonded to the less highly substituted carbon atom. Is this Markovnikov or non-Markovnikov orientation

Answers

All done for you no worries

When an unsymmetrical alkene such as propene is treated with N-bromosuccinimide in aqueous dimethyl sulfoxide, the major product has the bromine atom bonded to the less highly substituted carbon atom. This reaction describes a non-Markovnikov orientation.

In the reaction between an unsymmetrical alkene (such as propene) and N-bromosuccinimide (NBS) in the presence of aqueous dimethyl sulfoxide (DMSO), the major product is formed with the bromine atom bonded to the less highly substituted carbon atom of the alkene.

In Markovnikov's addition, the major product is formed by adding the electrophile (in this case, the bromine atom) to the carbon atom with more hydrogen atoms bonded to it. However, the given reaction exhibits non-Markovnikov selectivity, as the bromine atom adds to the less substituted carbon atom.

This non-Markovnikov selectivity can be attributed to the presence of DMSO, which acts as a polar solvent and helps generate a bromine radical (Br•). The radical intermediate can then undergo reaction with the alkene, leading to the observed regioselectivity where the bromine atom adds to the less substituted carbon. This process is known as a radical addition reaction.

Hence, the reaction demonstrates a non-Markovnikov orientation due to the addition of the bromine atom to the less highly substituted carbon atom of the propene molecule.

Learn more about the Markovnikov rule here:

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Volume of water is 35 cm3 and mass of water is 60 gram, what is the density of the water.​

Answers

Answer:

p = 1.714 g/cm3

Explanation:

Density Equation

p=mV

Where:

p = density

m = mass  = 60g

V = volume = 35cm3

p = 60g x 35cm3

p = 1.714 g/cm3

p=1.714g/cm³

Explanation:

v=35cm³

m=60g

P=mass/volume (density formula)

=60/35

=1.714g/cm³

Rubidium is ______ potassium in the periodic table. lodine is ______ bromine in the periodic table. Therefore, the rubidium ion is __________ than the potassium ion, and the iodine ion is___________ than the bromide ion. The _______ the distance between the rubidium ion and the iodide ion is the potassium ion and the bromide ion. Therefore, the energy associated with the interaction between rubidium and iodide is________ atomic radius means that than that between , and the lattice energy of potassium bromide is ________ more exothermidc.

Answers

Answer:

The given blanks can be filled with below, below, larger, larger, larger, larger and smaller.

Explanation:

In the periodic table, rubidium comes below the potassium, and iodine comes below bromine. Therefore, it can be said that the ion of rubidium is larger in comparison to potassium ion, and similarly the ion of iodine is larger in comparison to the ion of bromine.  

When the atomic radius is larger it signifies that the distance in between the ion of iodine and the ion of rubidium is larger in comparison to that between the ion of potassium and the ion of bromine. Thus, smaller energy is associated with the interaction between iodine and rubidium, and potassium bromide's lattice energy is more exothermic.  

Why are there different theories about the effects of global warming?

Answers

Because many people have different views on reality.
Because how can we be so sure? Theories are just predictions so there’s really no telling what the true effects of global warming are as new information is being gathered every day.

Which of these tasks would a geologist be most likely to perform?
A. Determining the species of a recently collected specimen
O B. Hypothesizing how pieces of ancient pottery were used
O C. Creating a new kind of material using polymers
O D. Determining the best method to extract underground natural gas
SUBMIT

Answers

Answer:

Explanation:

O B. Hypothesizing how pieces of ancient pottery were used

how many molecules (not moles) of NH3 are produced from 5.25x10^-4 g of H2?

due in a few, please help. will mark as brainliest

Answers

Answer:

not 100% but i think its 1.57x10^20

Explanation:

5.25x10^-4g / 2.016g

2.60x10^-4 x 6.022x10^23= 1.56x10^20 molecules

In this lab, you are to carry out the formation of a Grignard reagent from 1-bromo-benzene andits subsequent reaction with solid carbon dioxide (CO2) followed by acidic workup (using HCl asthe acid). Write the overall reaction and product(s) that you expect.

Answers

Answer:

(A). C6H5Br + Mg(in ether) -----------> C6H5MgBr.

(B). C6H5MgBr + O = C = O -----------> C6H5-COO^- Mg^+ Br.

(C). C6H5-COO^- Mg^+ Br + HCl --------> C6H5-COOH + Mg^+Br(OH).

PRODUCTS=> C6H5-COOH and Mg^+Br(OH).

Explanation:

A Grignard reagent is a reagent that/which is an organometallic compound that is R -Mg- X. The R = alkyl, vinyl or allyl and the X = halogens.

It must be noted that an important reaction of Grignard reagent is its reaction with compounds containing the Carbonyl that is -CO functional group and this kind of Reaction is known as a Grignard Reaction.

So, in this question we are told that;

=> "1-bromo-benzene andits subsequent reaction with solid carbon dioxide (CO2) followed by acidic workup (using HCl asthe acid). "

Thus;

(A). C6H5Br + Mg(in ether) -----------> C6H5MgBr.

(B). C6H5MgBr + O = C = O -----------> C6H5-COO^- Mg^+ Br.

(C). C6H5-COO^- Mg^+ Br + HCl --------> C6H5-COOH + Mg^+Br(OH).

why are the products of light reaction of photosythesis important

Answers

Answer: light reaction produces oxygen and water as we know the general importance of oxygen and water they are useful for organism to survive if plants do not produce oxygen then how could we get oxygen from the environment

The functional groups in an organic compound can frequently be deduced from its infrared absorption spectrum. A compound containing C, H, and O exhibits intense absorption at 1720 cm-1. No additional information is available. List possible classes for which there is positive evidence.
Relative absorption intensity: (s)=strong, (m)=medium, (w)=weak.

What functional class(es) does the compound belong to?
List only classes for which evidence is given here. Attach no significance to evidence not cited explicitly.
Do not over-interpret exact absorption band positions. None of your inferences should depend on small differences like 10 to 20 cm-1.

a. alkane (List only if no other functional class applies.)
b. alkene h. amine
c. terminal alkyne i. aldehyde or ketone
d. internal alkyne j. carboxylic acid
e. arene k. ester
f. alcohol l. nitrile
g. ether

Answers

Answer:

The class of this compound is aldehyde or ketone (i).

Explanation:

Absorption peak at 1720 cm-1 shows the presence of a carbonyl group, possibly an aldehyde or ketone with C=O bond.

Further information on molecular formula would be required for structural elucidation.

Which of the following is evidence for a physical change? A) burning B) fizzing C) evaporating D) rusting

Answers

The answer is D) rusting
I’m not sure and if it’s wrong I’m so sorry

Answer:c

Explanation: rusting, burning and fuzzing are all examples of chemical reactions/changes.



Pick the odd one out?


Ethanol

Hexane

Oil

Carbon tetrachloride

Answers

Answer: Ethanol is the odd one out.

Explanation:

A polar compound is defined as the compound which is formed when there is a difference of electronegativities between the atoms. It is also defined as the bond which is formed due to the unequal sharing of electrons between the atoms.

Non-polar compound is defined as the compound which is formed when there is no difference of electronegativities between the atoms or the polarities cancel out.

Hexane [tex](C_6H_{14}), Oil (mixture of hydrocarbons) and carbon tetrachloride [tex](CCl_4)[/tex] all are non polar whereas ethanol is polar due to electronegative difference between hydrogen and oxygen.

One proposed mechanism of the reaction of HBr with O2 is given here. HBr + O2 → HOOBr (slow) HOOBr + HBr → 2HOBr (fast) HOBr + HBr → H2O + Br2 (fast) What is the equation for the overall reaction?

Answers

Answer:

4 HBr + O2  →  + 2H2O + 2Br2

Explanation:

Based on the following reaction mechanism:

HBr + O2 → HOOBr (slow)

HOOBr + HBr → 2HOBr (fast)

HOBr + HBr → H2O + Br2 (fast)

The equation for the overall reaction is the sum of the three reactions in which intermediaries of reaction (HOBr and HOOBr are canceled). That is 1 + 2 + 2*(3):

HBr + O2 + HOOBr + HBr + 2HOBr + 2HBr → HOOBr + 2HOBr + 2H2O + 2Br2

4 HBr + O2  →  + 2H2O + 2Br2

Beeing this reaction the equation of the overall reaction.

A stock solution will be prepared by mixing the following chemicals together:

3.0 mL of 0.00200 M KSCN
10.0 mL of 0.200 M Fe(NO3)3
17.0 mL of 0.5 M HNO3

Determine the molar concentration of Fe(NO3)3 in the stock solution.

Answers

Answer:

0.067M Fe(NO3)3

Explanation:

A stock solution is a concentrated solution that is diluted to prepare the solutions that you will use.

The volume of the stock solution is 3.0mL + 10.0mL + 17.0mL= 30.0mL.

The ratio between volume of the aliquot (10.0mL) and total volume (30.0mL) is called dilution factor, that is: 30.0mL / 10.0mL = 3

That means the Fe(NO3)3 is diluted 3 times. That means the molar concentration of the stock solution is:

0.200M / 3 =

0.067M Fe(NO3)3

Using the following balanced chemical equation 8 H2 + S8à 8 H2S. Determine the mass of the product (molar mass = 34.08g/mol) if you start with 1.35 g of hydrogen and 6.86 g of S8 (Molar mass = 256.5 g/mole).

Answers

Answer: 7.29 g of [tex]H_2S[/tex] will be produced from the given masses of both reactants.

Explanation:

To calculate the moles :

[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]    

[tex]{\text{Moles of} H_2}=\frac{1.35g}{2.01g/mol}=0.672moles[/tex]

[tex]\text{Moles of} S_8=\frac{6.86g}{256.5g/mol}=0.0267moles[/tex]

[tex]8H_2+S_8\rightarrow 8H_2S[/tex]

According to stoichiometry :

1 mole of [tex]S_8[/tex] require = 8 moles of [tex]H_2[/tex]

Thus 0.0267 moles of [tex]S_8[/tex] will require=[tex]\frac{8}{1}\times 0.0267=0.214moles[/tex]  of [tex]H_2[/tex]

Thus [tex]S_8[/tex] is the limiting reagent as it limits the formation of product and [tex]H_2[/tex] is the excess reagent.

As 1 mole of [tex]S_8[/tex] give = 8 moles of [tex]H_2S[/tex]

Thus 0.0267 moles of [tex]S_8[/tex] give =[tex]\frac{8}{1}\times 0.0267=0.214moles[/tex]  of [tex]H_2S[/tex]

Mass of [tex]H_2S=moles\times {\text {Molar mass}}=0.214moles\times 34.08g/mol=7.29g[/tex]

Thus 7.29 g of [tex]H_2S[/tex] will be produced from the given masses of both reactants.

please help!!!! Chem question

Answers

Answer : The net ionic equation will be,

[tex]Ba^{2+}(aq)+SO_4^{2-}(aq)\rightarrow BaSO_4(s)[/tex]

Explanation :

In the net ionic equations, we are not include the spectator ions in the equations.

Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.

The given balanced ionic equation will be,

[tex]Ba(OH)_2(aq)+H_2SO_4(aq)\rightarrow 2H_2O(aq)+BaSO_4(s)[/tex]

The ionic equation in separated aqueous solution will be,

[tex]Ba^{2+}(aq)+2OH^-(aq)+2H^{+}(aq)+SO_4^{2-}(aq)\rightarrow BaSO_4(s)+2H^+(aq)+2OH^{-}(aq)[/tex]

In this equation, [tex]H^+\text{ and }OH^-[/tex] are the spectator ions.

By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.

The net ionic equation will be,

[tex]Ba^{2+}(aq)+SO_4^{2-}(aq)\rightarrow BaSO_4(s)[/tex]

1.Draw the born-Haber lattice energy cycle for sodium chloride. Explain the concept of resonance using the nitrate ion structure.

Answers

Answer:

1. Born Haber cycle is used to calculate enthalpy of formation of an ionic solid

2. Resonance structures are used to represent the bonding in some chemical species.

Explanation:

The Born–Haber cycle is a method popularly known in chemistry used in computing enthalpy. The enthalpy of formation of an ionic solid cannot be measured directly. The lattice enthalpy refers to the enthalpy change involved in the formation of an ionic compound from gaseous ions the process is exothermic process. A Born–Haber cycle works on the principle of Hess's law. It can be used to calculate the lattice enthalpy by comparing the standard enthalpy change of formation of the ionic compound from the elements to the enthalpy required to make gaseous ions from the elements.

Resonance is an idea introduced by Linus Pauling to explain chemical bonding from the valence bond perspective. The idea of resonance affords us the opportunity to describe the bonding in certain molecules by combining several structures called chemical or canonical structures. The real structure of the specie lie somewhere between the structures indicated by the resonance structures. The resonance structures of the nitrate ion are shown in the image attached.

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