exam 2 review problems sp17

What is the relationship between concentration and time for a reaction that is second order in [A]?

A plot of 1/[A] versus time is linear.

What is the rate constant for the first order reaction A (aq) → B (aq) when [A] = 1.22 M?

0.12 s-1

What is the rate law for the decomposition of N2O5 in carbon tetrachloride?

rate = k[N2O5]

How does an increase in temperature generally affect reaction rates?

Generally, reaction rate goes up regardless of whether the reaction is exothermic or endothermic.

What is the average rate of disappearance of I- between 400.0 s and 800.0 s given the options?

2.8 × 10^-5 M/s.

What is the concentration of S2O82- remaining at 400 s from the reaction S2O82- + 3I- → 2SO4 + I3-?

+0.045 M.

What is the rate law for the reaction 2A + 3B → products if it is first order in A and second order in B?

rate = k[A][B]^2.

What are the units of the rate constant for a reaction that is overall second order?

M^-1s^-1.

If the reaction rate increased by a factor of 9 when the concentration of B was tripled, what is the order of the reaction in B?

Second order.

If the reaction rate did not change when the concentration of B was tripled, what is the order of the reaction in B?

Zero order.

What is the order of the reaction in NH4+ for the reaction NH4+ + NO2- → N2 + 2H2O?

+1.

What is the value of k for a particular first-order reaction at 75.0 °C if the rate constant at 25.0 °C is 1.35 × 10^2 s^-1 and Ea = 55.3 kJ/mol?

3.34 × 10^3.

What is the equilibrium constant Keq for the reaction H2 + I2 ↔ 2HI with concentrations 0.20 M for H2, 0.034 M for I2, and 0.55 M for HI?

44.

How can the number of moles of SO3 be increased according to Le Châtelier's Principle for the reaction 2SO2 + O2 ↔ 2SO3?

Increasing the amount of SO2.

What is the equilibrium constant expression for CO2 + 2H2 ↔ CH3OH?

Keq = [CH3OH] / ([CO2][H2]^2).

If Kp = 1.10 at 250.0 °C for the reaction PCl5 ↔ PCl3 + Cl2, what is the value of Kc?

2.56 × 10^-2.

Calculate Keq for the equilibrium N2O4 ↔ 2NO2 if 9.20 × 10^-3 mol of N2O4 is initially charged and 5.98 × 10^-3 mol remains at equilibrium.

0.197.

At equilibrium in the reaction H2 + Br2 ↔ 2HBr, if there are 0.546 mol of H2 and 0.682 mol of H2 initially, how many moles of Br2 are present?

0.304.

What does it mean if Q < K for a reaction?

It means the reverse reaction will proceed to form more reactants.

What is the equilibrium pressure of NO2 for the reaction NO + SO3 ⇌ NO2 + SO2 with Kp = 0.0118?

0.084 atm.

If C + H2O ↔ CO + H2, what is the effect of adding more C on the amount of hydrogen gas?

No effect on the quantity of hydrogen gas.

What happens if H2O is removed from the equilibrium reaction C + H2O ↔ CO + H2?

Less hydrogen gas will be formed.

What is the effect of increasing the temperature on the endothermic reaction C + H2O ↔ CO + H2?

More hydrogen gas will be formed.

What happens if the volume of the reaction mixture C + H2O ↔ CO + H2 is increased?

More hydrogen gas will be formed.

What is the effect of adding a catalyst in the reaction C + H2O ↔ CO + H2?

No effect.