Question 1

When vinegar ($$\mathrm{CH_3COOH}) $$and baking soda ($$\mathrm{$$NaHCO_3$$}) $$are combined, the reaction is endothermic and releases $$\mathrm{CO_2$}$$ gas. What would you expect to observe if you touch the test tube during the reaction, and what is the sign of $$\Delta G$$ for this process?

Accepted Answer

The test tube feels cold; $$\Delta G is $$negative.

Question 2

Which of the following best defines the free energy change ($$\Delta G) $$for a chemical reaction?

Accepted Answer

$$\Delta G is $$the energy available to do work during a reaction at constant temperature and pressure.

Question 3

Which of the following reactions is exothermic?

Accepted Answer

A reaction where the test tube gets hot when two solids are combined.

Question 4

On a reaction energy diagram, if the products are lower in energy than the reactants, the reaction is classified as:

Accepted Answer

Exergonic

Question 5

Which of the following changes would result in a positive entropy change ($$\Delta S$$)?

Accepted Answer

Digestion of a meal.

Question 6

Which process is spontaneous?

Accepted Answer

A hot bowl of oatmeal cooling on the table.

Question 7

Calculate the number of Calories in a chocolate chip cookie containing 17 g carbohydrate, 1 g protein, and 7 g fat. (Use: 4 Cal/g for carbohydrate and protein, 9 Cal/g for fat.)

Accepted Answer

113 Calories

Question 8

Which of the following would increase the rate of a chemical reaction?

Accepted Answer

Adding a catalyst.

Question 9

Enzymes increase the rate of biological reactions by:

Accepted Answer

Lowering the activation energy.

Question 10

Which of the following is an example of a decomposition reaction?

Accepted Answer

$$\mathrm{C_4H_{10}O_2$(g) \rightarrow 2C_2H_4O(g) + 2CO_2(g)}$$

Question 11

Which of the following statements about exergonic and endergonic reactions is correct?

Accepted Answer

Exergonic reactions release free energy and have a negative $$\Delta G.$$

Question 12

Which of the following changes would result in a negative entropy change ($$\Delta S$$)?

Accepted Answer

Cleaning up your bedroom.

Question 13

Which of the following is an example of oxidation?

Accepted Answer

Aluminum metal forms aluminum oxide ($$\mathrm{Al_2O_3}).$$

Question 14

Which of the following best describes the effect of increasing the temperature on the rate of a chemical reaction?

Accepted Answer

It increases the frequency of collisions between reactant molecules.

Question 15

Which of the following is a synthesis reaction?

Accepted Answer

$$\mathrm{N_2$(g) + 3H_2(g) \rightarrow 2NH_3(g)}$$

Question 16

Which of the following would decrease the rate of a chemical reaction?

Accepted Answer

Decreasing the amount of one of the reactants.

Question 17

Which of the following is true about a reaction that must be heated for it to continue?

Accepted Answer

It is endothermic.

Question 18

Which of the following is a real-life example of a nonspontaneous process?

Accepted Answer

Walking on a treadmill at the gym.

Question 19

What is the balanced equation for the complete combustion of ethane ($$\mathrm{C_2H_6}$$)?

Accepted Answer

$$\mathrm{2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O}$$

Question 20

Which of the following would increase the rate of caramelizing onions?

Accepted Answer

Cooking on a medium-high stove setting.

Thermodynamics, Kinetics, and Chemical Reactions Study Guide (GOB Chemistry)

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