General Chemistry 2: Chemical Equilibrium

A 1.9 L vessel contains a gaseous mixture with 0.455 mol SO$_2$, 0.183 mol O$_2$, and 0.568 mol SO$_3$. Is the reaction at equilibrium? If not, what is the direction of the reaction?

2 SO$_2$ + O$_2$ $\leftrightharpoons$ 2 SO$_3$, K$_C$ = 280

A 1 L reaction vessel contains 2.5 mol A, 3 mol B, and initially 0 C. Find the concentrations of all species at equilibrium.

A + 2B $\leftrightharpoons$ 3 C , K$_C$ = 0.25

Find the equilibirium concentrations when starting with 0.50 M H$_2$ and 0.50 M Br$_2$

H$_2$ + Br$_2$ $\leftrightharpoons$ 2 HBr , K$_C$ = 143

0.20 M I$_2$ is placed in a reaction vessel. Find the concentrations of I$_2$ and I at equilibrium.

I$_2$ (g) $\leftrightharpoons$ 2 I (g) , K$_C$ = 3.8 x 10$^{-5}$

Starting with 0.50 M N$_2$O$_4$, calculate the equilbrium concentrations of all species involved in the reaction below.

N$_2$O$_4$ $\leftrightharpoons$ 2 NO$_2$ K$_C$ = 1.2

Find equilbirium concentrations of each species when starting with 3.0 M I$_2$

I$_2$ (g) $\leftrightharpoons$ 2 I (g) , K$_C$ = 3.8 x 10$^{-5}$

A 3.050 L reaction vessel contains 0.3500 mol CO, 0 mol Cl$_2$, 0.05500 mol COCl$_2$. Find the molarity of Cl$_2$ at equilibrium.

CO + Cl$_2$ $\leftrightharpoons$ COCl$_2$ , K$_C$ = 1200

A 2.5 L reaction vessel contains 0.55 mol PCl$_5$, 0.55 mol PCl$_3$, and 0 mol Cl$_2$. Find the molarity of Cl$_2$ at equilibrium.

PCl$_5$ $\leftrightharpoons$ PCl$_3$ + Cl$_2$ , K$_C$ = 3.8 x 10$^{-2}$

A 2.16 L reaction vessel contains 0.186 mol HCONH$_2$, and 0 mol of NH$_3$ and CO. How many moles of each substance are in the equilibrium mixture at 400 K? What is the pressure in the vessel?

HCONH$_2$ $\leftrightharpoons$ NH$_3$ + CO , K$_C$ = 4.84

At 1000 K, 0.250 mol SO$_2$ and 0.200 mol O$_2$ react in a 10.0 L reaction vessel to form 0.162 mol of SO$_3$ at equilibrium. What is K$_{eq}$ at 1000 K for the reaction?

2 SO$_2$ (g) + O$_2$ (g) $\leftrightharpoons$ 2 SO$_3$ (g)

0.800 moles of N$_2$ (g) are placed in a 7.00 L flask with 3.00 moles of H$_2$ and allowed to react for some time. After several hours the concentrations of H$_2$ (g) is measured at 0.278 M. What is the equilibrium constant for the reaction at this temperature?

N$_2$ (g) + 3 H$_2$ (g) $\leftrightharpoons$ 2 NH$_3$ (g)

Predict the effect an increase in H$_2$ would have on the following reaction. What if we increase the temperature? If we remove H$_2$O?

CO (g) + H$_2$O (g) $\leftrightharpoons$ CO$_2$ (g) + H$_2$ (g) + heat, K$_C$ = 5.10

3 A(s) + 5 B(g) $\leftrightharpoons$ 5 C(g) + 6 D(s) $\triangle$H = 0 kJ

A. Predict the change in A when D is added

B. Predict the direction of reaction when the pressure is increased

C. Predict the direction of reaction when the heat is increased

Determine how the following changes will effect the concentrations of the reactants and products.

2 NO$_2$ (g) $\leftrightharpoons$ N$_2$O$_4$ (g) $\triangle$H = -58 kJ

A. Addition of N$_2$O$_4$

B. Removal of NO$_2$

C. Increase in volume

D. Decrease in temperature

heat + 2 NO$_2$(g) $\leftrightharpoons$ N$_2$O$_4$(g)

Which of the following changes will not be effective in increasing the amount of N$_2$O$_4$? (more than one answer may be chosen)

a decrease in volume, an increase in heat, an addition of N$_2$, or removal of N$_2$O$_4$

A vessel contains 0.5 M acetic acid, which dissociates as shown below. What is the concentration of the acetate ion at equilibrium, given the K$_a$ below?

CH$_3$COOH (aq) $\leftrightharpoons$ CH$_3$OO$^{-}$ (aq) + H$^+$ (aq) , K$_a$ = 1.8 x 10$^{-5}$