CHEM111, EXAM 2, F11 B You must show all work for credit

Name_________________________________________

1. (10 points) Calculate the molarity of a solution prepared by dissolving 5.623 g of NaHCO3 in enough water to make 250.0 mL of solution.

2. (12 points) Calcium carbonate reacts with hydrochloric acid according to the following equation: CaCO3(s) + 2 HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l) If it took 35.0 mL of 0.125M HCl solution to neutralize a sample of pure calcium carbonate what is the mass of the calcium carbonate?

3. (6 points) In the following reaction: Mg(s) + 2 H+ → Mg2+(aq) + H2(g) (a) identify the species being reduced

(b) identify the oxidizing agent

CHEM111, EXAM 2, F11 B You must show all work for credit

Name_________________________________________

4. (12 points) The ∆Hrxn for the complete combustion of 1 mole acetone (C3H6O) is -1790 kJ: C3H6O(l) + 4 O2(g) → 3 CO2(g) + 4 H2O(l) Calculate the ∆Hf° of acetone.

5. (16 points) Write balanced net ionic equations for the reactions that occur when each of the following solutions are mixed. If no reaction occurs write no reaction. Hint not all reactions are precipitation reactions. (a) KNO3 + CaCl2 →

(b) CaBr2 + K2CO3

(c) HNO3 + NH3 →

(d) K3PO4 + CoBr2 →

CHEM111, EXAM 2, F11 B You must show all work for credit

Name_________________________________________

6. (12 points) At one time, a common means of forming small quantities of oxygen gas in the laboratory was to heat KClO3: 2 KClO3(s) → 2 KCl(s) +3 O2(g) ∆H = -89.4KJ What is the ∆H when 10.55 g of KClO3 reacts?

7. (15 points) Lithium and nitrogen react to produce lithium nitride 6 Li(s) + N2(g) → 2 Li3N (a) If 5.00 g of each reactant is used what is the maximum amount of Li3N that can be produced? (b) If 7.40 g was Li3N was actually obtained, what is the percent yield?

CHEM111, EXAM 2, F11 B You must show all work for credit

Name_________________________________________

8. (10 points) Critique the following instructions for preparing 1 L of a 1.00 M solution starting with