Chapter 18 Review Reaction Rates and Equilibrium Possible

Chapter 18 Review “Reaction Rates and Equilibrium”

Possible Essays n n List the four factors that affect reaction rate and describe the effects that they have. What are three stresses that can change the equilibrium of a reaction and explain how the stress would be relieved. What are the two factors that determine the spontaneity of a reaction and describe the favorable outcomes. Make sure to include how Gibbs Free Energy comes into play. What is the difference between a spontaneous and nonspontaneous reaction? Why can a spontaneous reaction appear to be nonspontaneous?

Chapter 18 Review n Energy that is available to do work is called ____. n What is the name of the minimum energy that colliding particles must have in order to react?

Chapter 18 Review n A substance that interferes with a catalyst is a(n) ____. n What is the arrangement of atoms at the peak of an energy barrier? n At equilibrium, what is the rate of production of reactants compared with the rate of production of products?

Chapter 18 Review n What is the equilibrium constant expression for the following reaction: C(s) + O 2(g) ↔ CO 2(g) n Which of the following is true about the combustion of carbon: a) the reaction is spontaneous, or b) entropy decreases? n The rate of a chemical reaction normally ____ as reactant concentration increases.

Chapter 18 Review n Why does a higher concentration make a reaction faster? n The amount of disorder in a system is measured by its ____. n What units represent a reaction rate? n For a complex reaction, the reaction progress curve has several ____.

Chapter 18 Review n What happens to a reaction at equilibrium when more reactant is added to the system? n Which reaction results in the greatest increase in entropy: a) A → B, or b) A → 2 B n If a reaction has an equilibrium constant (Keq) just greater than 1, how do we interpret that information?

Chapter 18 Review n. A catalyst works by ____. n If sulfur dioxide and oxygen can be made into sulfur trioxide, what is the reverse reaction? n Which variable is NOT required to calculate the Gibbs free-energy change for a chemical reaction: a) change in enthalpy, or b) temperature in o. C?

Chapter 18 Review n What is the effect of adding more water to the following equilibrium reaction: CO 2 + H 2 O ↔ H 2 CO 3 n In an endothermic reaction at equilibrium, what is the effect of raising the temperature? n The energy that is available to do work in a reaction is called ____.

Chapter 18 Review n What is the numerical value (+ or -) of Gibbs free-energy change for a spontaneous reaction? n At what stage of a reaction do atoms have the highest energy? n Which of the following systems has the highest entropy: a) 10 m. L of water at 50 o. C, or b) 10 m. L of water at 100 o. C?

Chapter 18 Review n What happens to a catalyst in a reaction? n An elementary reaction converts reactants to products in ____. n Activation energy is ____.

Chapter 18 Review n Consider the reaction: N 2(g) + 3 H 2(g) ↔ 2 NH 3(g) What is the effect of decreasing the volume on the contained gases? n Spontaneous reactions always ____ free energy. n Why does a higher temperature cause a reaction to go faster?

Chapter 18 Review n What 2 factors determine whether or not a reaction is spontaneous? n What physical state of nitrogen has the highest entropy? n What is another name for the catalysts in your body?

Chapter 18 Review n What is the order of the following reaction: A + 2 B → C + D n Why does a catalyst cause a reaction to proceed faster? n In an equilibrium reaction with a Keq of 1 x 108, the ____ are favored. n Which of the following explains why melting of ice is spontaneous at room temperature and pressure: a) it is accompanied by an increase in entropy, or b) it is accompanied by an increase in energy?

Chapter 18 Review n The Keq of a reaction is 4 x 10 -7. At equilibrium, the ____ are favored. n Another name for the activated complex is ____. n Which change would shift the following reaction to the right: 4 HCl(g) + O 2(g) ↔ 2 Cl 2(g) + 2 H 2 O(g) a) decrease of pressure, or b) increase of pressure?

Chapter 18 Review n In which of these systems is the entropy decreasing: a) salt dissolving in water, or b) a liquid cooling? n Given: 2 NCl. O(g) ↔ 2 NO(g) + Cl 2(g) An analysis of the equilibrium mixture in a 1 L flask is: NCl. O = 1. 6 mol; NO = 6. 4 mol; Cl 2 = 0. 49 mol. Calculate the value of Keq.

Chapter 18 Review n In a two-step reaction mechanism, how many elementary reactions occur? n The Ksp of calcium hydroxide is 6. 5 x 10 -6. If 0. 10 mol of sodium hydroxide is added to 1 L of 0. 0010 M Ca(OH)2, what is the final concentration of the calcium ion?

Chapter 18 Review n. A mixture of hydrogen and iodine are in equilibrium with hydrogen iodide, as shown in the equation: H 2 + I 2 ↔ 2 HI Calculate the concentration of HI when the Keq is 1 x 105, the equilibrium concentration of H 2 is 0. 04 M, and the equilibrium concentration of I 2 is 0. 009 M.

Chapter 18 Review