Chapter 10 Pre-Lecture HW

An intermediate step in the process that ultimately produces sulfuric acid, is the catalytic oxidation of SO2 to SO3. Vanadium(V) oxide is the catalyst. The three chemical species in the reaction are in equilibrium as follows: 2SO2(g)+O2(g)⇌2SO3(g) Which of the following are true statements about this reaction? When SO2 is mixed with O2 in a container, the initial rate of the forward reaction (production of SO3) is faster than the initial rate of the reverse reaction (production of SO2). As SO2 is used up and SO3 accumulates, the rate of the forward reaction increases and the rate of the reverse reaction decreases. At equilibrium the rate of production of SO3 reaches zero. At equilibrium the concentration of SO2 will no longer be changing.

1 and 4 are true

1.)The Haber process is typically carried out at a temperature of approximately 500 ∘C. What would happen to the rate of the forward reaction if the temperature were lowered to 100 ∘C? 2.)What would happen to the rate of the forward reaction if the concentration of nitrogen were decreased? 3.)Which of the following would increase the rate of the reverse reaction? 4.)What will happen to the rates of the forward and reverse reactions when a catalyst is added?

1.)decrease 2.)decrease 3.)increasing the concentration of ammonia 4.)Both forward and reverse rates increase.

1.)A chemical reaction is at equilibrium when 2.)A reaction that has a large equilibrium constant has 3.)If a reaction is exothermic and produces large quantities of heat reaching equilibrium, its equilibrium constant will be 4.)Consider the reaction N2O4(g)→2NO2(g) where N2O4 is colorless and NO2 is brown. At a temperature of 5∘C, the reaction is colorless at equilibrium. This indicates that the equilibrium constant for this reaction at this temperature is

1.)the rate of the forward reaction equals the rate of the reverse reaction. 2.)more products then reactants at equilibrium. 3.)greater than zero. 4.)small (less than 1).

What is the numerical value of Kc for the following reaction if the equilibrium mixture contains 0.51 M C3H6O, 0.30 M O2, 1.8 M CO2, and 2.0 M H2O?C3H6O(g) + 4 O2(g) ↔ 3 CO2(g) + 3 H2O(g)

1.1 x 10^4

Photosynthesis can be represented by 6CO2(g)+6H2O(l)⇌C6H12O6(s)+6O2(g) Which of the following will be false when the photosynthesis reaction reaches equilibrium?The rate of formation of O2 is equal to the rate of formation of CO2.The concentration of O2 will begin decreasing.The concentrations of CO2 and O2 will not change.The concentrations of CO2 and O2 will be equal.

2 and 4 are false

Acetic acid (CH3COOH) is a weak acid that partially dissociates in water. Given the reactionCH3COOH(aq) ↔ CH3COO−(aq) + H+(aq)and Kc = 1.8 x 10−5, if the concentration of the acetic acid is 0.016 M and the concentration of the acetate ion is 0.92 M, what is the [H+]?

3.1 x 10^-7

Which of the following actions will cause the equilibrium to shift such that the concentration of NO gas will increase? 2NO(g) + 2H2(g) ⇌ N2(g)+2H2O+heat

Increase the concentration of H2O(g)

Select the equilibrium expression, Kc, for the following reaction:CH4(g) + 2 H2S(g) ↔ CS2(g) + 4 H2(g)

Kc = [H2]4 [CS2] [CH4] [H2S]2

Which equilibrium reaction will experience a shift towards the products in equilibrium position when the concentration of Ni2+ is increased?

Ni2+(aq)+6NH3(aq)⇌[Ni(NH3)6]2+

Which of the following statements is true about a reversible reaction that has reached chemical equilibrium?

The forward and reverse reactions occur at the same rate.

An equilibrium reaction has a Kc of 1.4 x 109. Which of the following descriptions accurately describes the chemical equilibrium for this reaction?

The magnitude of Kc is large, indicating the concentrations of the products are greater than the concentrations of the reactants at equilibrium. The equilibrium is said to favor the products.

For a chemical reaction to occur, three factors must be met. Which of the following factors is required for a reaction to occur?

The reactants must align properly to break and form bonds.

If the reaction N2(g)+3H2(g)⇌2NH3(g) is at equilibrium, what direction will the reaction shift if NH3 gas is added?

The reaction will shift to produce reactants.

Le Chatelier's principle describes the effect of changing conditions on a chemical reaction that was previously at equilibrium. Choose the statement that correctly describes the possible effects.

When oxygen is removed from a combustion reaction, the reaction slows down or stops.

Which of the following conditions will decrease the rate of a reaction?

a decrease in temperature

Consider the following chemical reaction:Heat + 2 NOCl(g) ↔ 2 NO(g) + Cl2(g) Which of the conditions listed below will result in the equilibrium shifting toward the reactant side according to Le Chatelier's principle?

increasing the concentration of Cl2(g)

In the following reaction,H3PO4(aq) + H2O(l) ( H2PO4−(aq) + H3O+(aq)what happens when more H2PO4−(aq) is added to the solution?

the equilibrium shifts to the left, creating more H3PO4(aq).

Consider the exothermic reaction Fe2O3(s)+2Al(s)⇌Al2O3(s)+2Fe(s) In what direction will the equilibrium shift when heat is removed?

the equilibrium will shift towards the products

When this reaction in equilibrium is heated, a red/brown color persists. What is true about this reaction? 2NO2(g)brown/red⇋N2O4(g)colorless

the reaction is exothermic

If an endothermic reaction is at equilibrium, how will the equilibrium shift when heat is added to the reaction?

the reaction will shift towards the products

Consider the reaction 2H2(g)+O2(g)⇌2H2O(g) How will the equilibrium shift when hydrogen gas is removed?

the system will shift towards the reactants