Question 1

Which one of the following statements is correct in relation to an endothermic reaction?

Accepted Answer

The value of the activation energy is >0 and the value of ΔH is >0.

Answer

The value of the activation energy is <0 and the value of ΔH is >0.

Answer

The value of the activation energy is >0 and the value of ΔH is <0.

Answer

The value of the activation energy is <0 and the value of ΔH is <0.

Question 2

The energy profile diagram shown below is for the following reaction. CO2(g) + NO(g) ⇌ CO(g) + NO2(g).  What is ΔH of the forward reaction, in kJ/mol?

Accepted Answer

+260

Answer

+130

Answer

+230

Answer

-170

Question 3

The energy profile diagram shown below is for the following reaction.
	CO2(g) + NO(g) ⇌ CO(g) + NO2(g)
What is the activation energy of the reverse reaction, in kJ/mol?

Accepted Answer

130

Answer

360

Answer

230

Answer

40

Question 4

Consider the following reaction equations:
I: A(g) + B(g) ⇌ 2C(g)		ΔH = +180 kJ/mol
II: D(g) + 3E2(g) ⇌ 2F(g) 	ΔH = -90 kJ/mol
III. 2G(g) ⇌ H(g) + I(g) 	ΔH = -180 kJ/mol
From a comparison of the enthalpy changes, ΔH, which of the following is definitely true?

Accepted Answer

No information about activation energy can be deduced.

Answer

Activation energy of equation I= activation energy of equation III.

Answer

Activation energy of equation I> activation energy of equation II.

Answer

Activation energy of equation I< activation energy of equation II.

Question 5

Select the correct statement about an open system.

Accepted Answer

Energy and matter can both be exchanged with the surroundings.

Answer

Matter can be exchanged with the surroundings but not matter

Answer

Neither energy nor matter are exchanged with the surroundings

Answer

Energy can be exchanged with the surroundings but not matter

Question 6

Which of the following is an example of an irreversible reaction?

Accepted Answer

Boiling an egg

Answer

Mixing of ethanol and water

Answer

Freezing a sample of water

Answer

The air trapped in a sealed soft drink container

Question 7

Which of the following systems is not at equilibrium?

Accepted Answer

A burning candle

Answer

A gaseous reaction in a sealed container stored at constant temperature

Answer

A sealed bottle of soft drink

Answer

A saturated solution of salt with solid salt on the bottom of the beaker

Question 8

Water vapor reacts with chlorine according to the following equation:
$2H_2O(g)$ + $2Cl_2(g)$ ⇌ 4HCl(g) + $O_2(g)$
At a particular temperature, the value of the equilibrium constant, $K_{eq}$, for this reaction is $4.0x10^{-4}$. At the same temperature, what is the value of the equilibrium constant for the following reaction?
2HCl(g) + $½O_2(g)$ ⇌ $H_2O$(g) + $Cl_2(g)$

Accepted Answer

50

Answer

$2x10^{-4}$

Answer

$2x10^3$

Answer

$2x10^{-2}$

Question 9

Consider the following equation:
A + 3B ⇌ 2C + 4D
The correct expression for the equilibrium constant for the equation is:

Accepted Answer

https://uploads.quizalize.com/ce2b13b9-7afe-474f-8c2e-665284e8add3/question/49d0e445af2b9c3060131bff8247261372d16989.JPG

Answer

https://uploads.quizalize.com/ce2b13b9-7afe-474f-8c2e-665284e8add3/question/83a7a438b23ef3136d1d88ca93edcfedb4952cee.JPG

Answer

https://uploads.quizalize.com/ce2b13b9-7afe-474f-8c2e-665284e8add3/question/651621da6865bc3b53d5967b9a5d1230ea6e26e1.JPG

Answer

https://uploads.quizalize.com/ce2b13b9-7afe-474f-8c2e-665284e8add3/question/5d35586ba3a07dbe0411d013362e61acf911cba7.JPG

Question 10

In which of the following reactions does increasing the concentration of W result in an initial increase in the rate of the forward reaction?
2W + 2X ⇌ 2Y + Z
X W ⇌ Y + 2Z
2X ⇌ 2W + Y

Accepted Answer

I and II only

Answer

II and III only

Answer

I, II, and III

Answer

I and III only

Question 11

In a sealed vessel, nitrogen monoxide, oxygen and nitrogen dioxide form the following equilibrium:
2NO(g) + $O_2(g)$ ⇌ $2NO_2(g)$    	   ΔH = -114 kJ/mol
Which of the following sets of conditions is likely to lead to the highest yield of nitrogen dioxide gas?

Accepted Answer

$200^0C$ and 2 atm pressure

Answer

$300^0C$ and 1 atm pressure

Answer

$200^0C$ and 1 atm pressure

Answer

$300^0C$ and 2 atm pressure

Question 12

A sample of NOC is allowed to come to equilibrium according to the following equation:
2NOCl(g) ⇌ 2NO(g) + $Cl_2(g)$
The volume of the mixture is halved and the mixture is allowed to come to a new equilibrium, the temperature remaining constant. At the new equilibrium, which of the following is true concerning chlorine?

Accepted Answer

The amount has decreased and the concentration has increased.

Answer

Both the amount and concentration have increased.

Answer

The amount has increased and the concentration has decreased.

Answer

Both the amount and concentration have decreased.

Question 13

The reaction between nitrogen monoxide and zone is:
NO(g) + $O_3(g)$ ⇌ $NO_2(g)$ + $O_2(g)$ 	Keq = $6x10^{34}$ at $25^0C$
Equal amounts of NO and $O_3$ are used. Which of the following statements cannot be inferred from the magnitude of the equilibrium constant?

Accepted Answer

The reaction has low activation energy.

Answer

At equilibrium, $[NO_2][O_2]>[NO][O_3]$

Answer

Very little ozone will remain at equilibrium

Answer

The position of equilibrium of the reaction lies well to the right

Question 14

Carbon dioxide gas dissolves to a small extent in water, forming carbonic acid in an exothermic reaction.
$CO_2(g)$ + $H_2O(l)$ ⇌ $H_2CO_3(aq)$           ΔH = -114 kJ/mol
$H_2CO_3(aq)$ + $H_2O(l)$ ⇌ $HCO_3^-(aq)$ + $H_3O^+(aq)$
This is the reaction involved in forming fizzy drinks.
Which of the following strategies would not increase the amount of dissolved carbon dioxide?

Accepted Answer

increasing the amount of $H_3O^+$ in the solution

Answer

Increasing pressure of the carbon dioxide gas

Answer

Increasing the concentration of carbon dioxide in the gas

Answer

Decreasing the temperature of the solution

Question 15

When $(NH_4)_2SO_4$ powder is stirred into water, which of the following occurs?

Accepted Answer

$NH_4^+$ and $SO_4^{2-}$ ions are released

Answer

$N^{3-}$, $H^+$ and $SO_4^{2-}$ ions are released

Answer

$NH_4^+$ and $SO_4^-$ ions are released

Answer

A precipitate is formed

Question 16

A precipitate could be formed from the reaction between which of the following pairs of solutions?

Accepted Answer

$Ba(NO_3)_2$ and $NaSO_4$

Answer

$NaNO_3$ and $BaCl_2$

Answer

$BaCl_2$ and $Ba(NO_3)_2$

Answer

$Ba(NO_3)_2$ and NaCl

Question 17

Which list contains only substances soluble in water?

Accepted Answer

$NH_4Cl,$ $Na_3PO_4$, $KCH_3COO$

Answer

$NH_4Cl,$ AgCl, $BaSO_4$

Answer

$CaCO_3,$ AgCl, $KCH_3COO$

Answer

$ZnCO_3,$ $BaSO_4,$ KI

Question 18

The molar solubility of $Ag^+$ ions in an AgBr solution at $25^0C$ is $7.31x10^{-7}$ mol/L. What is the value of the solubility product constant for AgBr?

Accepted Answer

$5.34x10^{-13}$

Answer

$7.31x10^{-7}$

Answer

$5.34x10^{-7}$

Answer

$8.44x10^{-4}$

Question 19

What is the equilibrium expression for the solubility product constant for $Ca_3(PO_4)_2?$

Accepted Answer

$K_{sp}$ = $[Ca^{2+}]^3[PO_4^{3-}]^2$

Answer

$K_{sp}$ = $[Ca_3(PO_4)_2]$

Answer

$K_{sp}$ = $[Ca^{2+}]^2[PO_4^{3-}]^3$

Answer

$K_{sp}$ = $[Ca^{2+}]^2[PO_4^{3-}]^2$

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