Exam 2 Review

Stoichiometry & Quantitative

100

What mass of Ca(NO3)2 is present in 0.350 mol of Ca(NO3)2?

What is 57.4 g? 

200

A reaction produces 9.60 g of product with a percent yield of 75.0%. What is the theoretical yield?

What is 12.8 g?

300

How many moles of CaCl2 are present in 250.0 mL of a 0.425⁢ MCaCl2 solution?

What is 0.106 mol?

400

A sample contains 3.00 ×10¹⁹ molecules of caffeine (C₈⁢H_10⁢N_4⁢O₂). What is the mass of caffeine in milligrams?

What is 9.68 mg?

500

A student reacts 12.0 g of iron(III) oxide with 4.00 g of aluminum according to Fe2⁢O3⁢ (s) +2⁢Al(s) →Al2⁢O3⁢ (s) +2Fe(s). What mass of iron metal can be produced?

What is 8.28 g Fe?

Aqueous Solutions & Solubility

100

Which one of the following substances behaves as a nonelectrolyte when dissolved in water: glucose (C6⁢H12⁢O6) or calcium chloride (CaCl2)?

What is glucose, C₆H₁₂O₆?

200

Which one of the following compounds is a weak base in water: Ba(OH)2, NH3, KOH, or NaOH?

What is NH₃?

300

Which one of the following compounds is expected to be soluble in water: AgBr, CaCO3, Na3⁢PO4, or PbI2?

What is Na₃PO₄?

400

A student dilutes 35.0 mL of 2.50⁢ MKNO3 solution to a final volume of 400.0 mL. What is the final molarity?

What is 0.219 M?

500

Which of the following reactions has a net ionic equation describing the formation of a solid precipitate?

(a) NaNO₃ (aq) + KCl (aq) → NaCl (aq) + KNO₃ (aq)
(b) HBr (aq) + LiOH (aq) → LiBr (aq) + H₂O (ℓ)
(c) Sr(NO₃)₂ (aq) + Na₂SO₄ (aq) → SrSO₄ (s) + 2NaNO₃ (aq)

(c) Sr(NO₃)₂ (aq) + Na₂SO₄ (aq) → SrSO₄ (s) + 2NaNO₃ (aq)

Balancing

100

H₂ (g) + N₂ (g) ⟶ NH₃ (g)

3H₂ (g) + 1N₂ (g) ⟶ 2NH₃ (g)

200

Fe (s) + O₂ (g) ⟶ Fe₂O₃ (s)

4 Fe (s) + 3 O₂ (g) ⟶ 2 Fe₂O₃ (s)

300

KClO₃⁢ (s) →KCl(s) +O₂ (g)

2KClO₃⁢ (s) →2KCl(s) + 3O₂ (g)

400

NH₃ (g) + O₂ (g) ⟶ N₂ (g) + H₂O (ℓ)

4NH₃ (g) + 3O₂ (g) ⟶ 2N₂ (g) + 6H₂O (ℓ)

500

C₆H₁₄ (ℓ) + O₂ (g) ⟶ CO₂ (g) + H₂O (ℓ)  

2C₆H₁₄ (ℓ) + 19O₂ (g) ⟶ 12CO₂ (g) + 14H₂O (ℓ)  

Bonus (Redox, Reaction types)

100

What is the oxidation number of nitrogen in the nitrate ion, NO₃⁻? 

+5

200

How would you classify the reaction H₂CO₃ (aq) → H₂O (ℓ) + CO₂ (g)?

(a) precipitation (b) synthesis (c) acid–base neutralization (d) decomposition

(d) decomposition

300

Which type of reaction is represented by 3⁢CaCl2⁢ (aq) +2⁢Na3⁢PO4⁢ (aq) →Ca3⁢(PO4)2⁢ (s) +6NaCl(aq)?

(a) combustion (b) precipitation (c) decomposition (d) acid–base neutralization

(b) precipitation

400

Zn (s) + S (s) --> ZnS (s)

What element is reduced? Oxidized? Reducing agent? Oxidizing agent?

S is reduced. Zn is oxidized. Zn is the reducing agent. S is the oxidizing agent

500

In the reaction Fe(s) +2⁢AgNO₃⁢ (aq) →Fe(NO₃)₂ (aq) +2Ag(s), which species is reduced?

What is Ag⁺ (aq)?