Question 1

Which of the following best describes a chemical reaction?

Accepted Answer

A process where substances change into new substances.

Question 2

Which equation represents the neutralization of a strong acid and a strong base?

Accepted Answer

$$\mathrm{HCl} + \mathrm{NaOH} \rightarrow \mathrm{NaCl} + \mathrm{H_2O}$$

Question 3

Which of the following is a physical transformation?

Accepted Answer

$$\mathrm{H_2O} (s) \rightarrow \mathrm{H_2O} (l)$$

Question 4

In the reaction $$2\mathrm{Al} (s) + 6\mathrm{HCl} (aq) \rightarrow 2\mathrm{$$AlCl_3$$} (s) + 3\mathrm{H_2$} (g)$$, what is the limiting reagent if you start with 10 mol Al and 30 mol HCl?

Accepted Answer

Neither, both are present in stoichiometric amounts

Question 5

Which law states that the total mass of reactants equals the total mass of products in a chemical reaction?

Accepted Answer

Law of Conservation of Mass

Question 6

A reaction is spontaneous if the change in Gibbs free energy ($$\Delta G) is$$:

Accepted Answer

$$\Delta G \u003c 0$$

Question 7

Which equation correctly relates the change in internal energy ($$\Delta U) to $$heat and work?

Accepted Answer

$$\Delta U = q + w$$

Question 8

Which of the following reactions is exothermic?

Accepted Answer

$$\mathrm{CH_4$} + 2\mathrm{O_2$} \rightarrow \mathrm{CO_2$} + 2\mathrm{H_2O}$$

Question 9

What is the effect of increasing temperature on the equilibrium constant ($$K) $$for an endothermic reaction?

Accepted Answer

K increases

Question 10

For the reaction $$\mathrm{H_2$} (g) + \mathrm{I_2$} (g) = 2\mathrm{HI} (g)$$, if $$K = 50$$ and $$Q = 10$$, what is the direction of the reaction?

Accepted Answer

Forward direction (more HI is produced)

Question 11

Which formula expresses the relationship between the standard Gibbs free energy change and the equilibrium constant?

Accepted Answer

$$\Delta G^\circ = -RT \ln K$$

Question 12

Which of the following best describes Le Châtelier’s principle?

Accepted Answer

When a system at equilibrium is disturbed, it shifts in a direction that counteracts the disturbance.

Question 13

Which of the following is an example of a chemical reaction occurring in daily life?

Accepted Answer

Rusting of iron

Question 14

In the reaction $$2\mathrm{C_2H_6} (g) + 7\mathrm{O_2$} (g) \rightarrow 4\mathrm{CO_2$} (g) + 6\mathrm{H_2O} (l)$$, what is the total number of oxygen atoms on the reactant side?

Accepted Answer

14

Question 15

Which variable is considered an intensive property?

Accepted Answer

Temperature

Question 16

For the reaction $$\mathrm{N_2$} (g) + 3\mathrm{H_2$} (g) = 2\mathrm{NH_3$} (g)$$, if you start with 10 mol N2 and 10 mol H2, what is the maximum reaction extent ($$\xi_{max}$$)?

Accepted Answer

$$\xi_{max} = 10 / 3 = 3.33$$ mol

Question 17

Which of the following statements about entropy ($$S) is $$correct?

Accepted Answer

High entropy means particles are more disordered or spread out.

Question 18

Which equation represents the Van't Hoff relation for the effect of temperature on equilibrium constant?

Accepted Answer

$$\ln \left( \frac{K_2$}{K_1$} \right) = -\frac{\Delta H^\circ}{R} \left( \frac{1}{T_2$} - \frac{1}{T_1$} \right)$$

Chemical Reactions and Thermodynamics: Progress, Equilibrium, and Spontaneity

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