Chemistry 30

Write balanced chemical equations for each of the following. Pay close attention to the physical states!

Also - you must include the charge when writing ions, otherwise your answer is incorrect.

Do not balance these equations using fractions for coefficients.

1. sulfur dioxide gas combines with oxygen gas to produce sulfur trioxide gas
2. carbon monoxide gas burns in gaseous oxygen to produce carbon dioxide gas
3. hydrogen chloride gas is produced from hydrogen gas and chlorine gas
4. nitrogen gas and oxygen gas combine to produce gaseous dinitrogen oxide
5. solid hydrogen cyanide dissolves to produce hydrogen ions and cyanide ions in solution
6. solid silver chloride dissolves to produce silver ions and chloride ions in solution
7. calcium ions and phosphate ions come out of solution to produce solid calcium phosphate

Solution

Write balanced chemical equations for each of the following. Pay close attention to the physical states!

a. sulfur dioxide gas combines with oxygen gas to produce sulfur trioxide gas

2 SO_{2 (g)} + O_{2 (g)} ↔ 2 SO_{3 (g)}

b. carbon monoxide gas burns in gaseous oxygen to produce carbon dioxide gas

2 CO _(g) + O_{2 (g)} ↔ 2 CO_{2 (g)}

c. hydrogen chloride gas is produced from hydrogen gas and chlorine gas

H_{2 (g)} + Cl_{2 (g)} ↔ 2 HCl_(g)

d. nitrogen gas and oxygen gas combine to produce gaseous dinitrogen oxide

2 N_{2 (g)} + O_{2 (g)} ↔ 2 N₂O _(g)

e. solid hydrogen cyanide dissolves to produce hydrogen ions and cyanide ions in solution

HCN_(s) ↔ H⁺_(aq) + CN^-_(aq)

f. solid silver chloride dissolves to produce silver ions and chloride ions in solution

AgCl_(s) ↔ Ag⁺_(aq) + Cl^-_(aq)

g. calcium ions and phosphate ions come out of solution to produce solid calcium phosphate

3 Ca²⁺_(aq) + 2 PO₄^3-_(aq) ↔ Ca₃(PO₄)_{2 (s)}

The equilibrium equation for the formation of ammonia is

N_{2 (g)} + 3 H_{2 (g)} ↔ 2 NH_{3 (g)}

At 200°C the concentrations of nitrogen, hydrogen, and ammonia at equilibrium are measured and found to be [N₂] = 2.12; [H₂] = 1.75, and [NH₃] = 84.3. Calculate K_eq at this temperature.

Solution:

For each of the following equilibrium systems, identify whether the reactants or products are favored at equilibrium, or whether they are equally favored.

For the reaction: carbon monoxide burns in oxygen to produce carbon dioxide.
You are given the following equilibrium conditions:

Calculate [CO]

Solution:

Begin by writing a balanced equation for the reaction:

2 CO_(g) + O_{2 (g)} ↔ 2 CO_{2 (g)} 

Next, set up the equilibrium constant expression and solve for the unknown, [CO]. You will find it easier to let [CO] = x while you rearrange the equation: