Question 1

Which of the following statements best describes an exothermic reaction?

Accepted Answer

It gives off heat to the surroundings, resulting in a negative $$\Delta H.$$

Question 2

A chemical reaction has $$\Delta H = -150 kJ $$and $$\Delta S = +200 J/K at$$ $$T = 298 K. $$What is the value of $$\Delta G$$ for this reaction?

Accepted Answer

$$\Delta G = -209.6 kJ$\ (\Delta G = \Delta H - T\Delta S = -150\ 	ext{kJ} - 298\ 	ext{K} 	imes 0.2\ 	ext{kJ/K} = -150 - 59.6 = -209.6\ 	ext{kJ})$$

Question 3

Which of the following changes will increase the rate of a chemical reaction?

Accepted Answer

Adding a catalyst

Question 4

Which statement about enzymes is TRUE?

Accepted Answer

Enzymes lower the activation energy and increase the rate of reaction.

Question 5

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

Accepted Answer

$$2H_2O_2 \rightarrow 2H_2O + O_2$

Question 6

Which reaction type is represented by the following equation: $$A + B \rightarrow AB$$?

Accepted Answer

Synthesis

Question 7

Combustion of hydrocarbons is considered irreversible because:

Accepted Answer

It is highly exothermic and rejoining the products requires too much energy.

Question 8

Which of the following best describes oxidation in organic molecules?

Accepted Answer

Gain of oxygen or loss of hydrogen

Question 9

In the following reaction, which species is oxidized? $$Fe^{2+}$$ + $$Cu^{2+}$$ \rightarrow $$Fe^{3+}$$ + $$Cu^{+}$$

Accepted Answer

$$Fe^{2+}$$

Question 10

Which molecule acts as an energy carrier in living systems, transferring energy between reactions?

Accepted Answer

ATP

Question 11

Which of the following is TRUE about condensation reactions?

Accepted Answer

Water is produced as two organic molecules are joined.

Question 12

What is the major product when water is added to an asymmetric alkene in a hydration reaction?

Accepted Answer

The $$-OH$$ group bonds to the carbon with more carbon groups attached.

Question 13

Which of the following is a hydrolyzable lipid?

Accepted Answer

Triglyceride (fat)

Question 14

Which equation correctly represents the relationship between free energy, enthalpy, and entropy?

Accepted Answer

$$\Delta G = \Delta H - T\Delta S$$

Question 15

Which of the following statements about catalysts is FALSE?

Accepted Answer

Catalysts are consumed during the reaction.

Question 16

A reaction has $$\Delta G \u003e 0. $$What does this indicate about the reaction?

Accepted Answer

It is nonspontaneous and requires energy input from the surroundings.

Question 17

Which of the following is an example of an exchange (single displacement) reaction?

Accepted Answer

$$AB + C \rightarrow AC + B$$

Question 18

Which factor does NOT increase the rate of a chemical reaction?

Accepted Answer

Decreasing the concentration of reactants

Question 19

During the complete combustion of propane ($$C_3H_8$$), what are the products?

Accepted Answer

$$CO_2$$ and $$H_2O$$

Question 20

Which of the following best describes a hydrolysis reaction?

Accepted Answer

Water is consumed and a molecule is split into two smaller molecules.

Chapter 5: Chemical Reactions – Thermodynamics and Energy in GOB Chemistry

Guida di studio - Domande di pratica