Question

Please answer the questions clearly, showing all working.

1(i). Balance the following equations, and then write the net ionic equation

(a) (NH4)2CO3(aq) + Cu(NO3)2(aq) → CuCO3(s) + NH4NO3(aq)

(b) Mg(OH)2(s) + HCl(aq) → MgCl2(aq) + H2O(l)

(c) BaCO3(s) + HBr(aq) → BaBr2(aq) + H2O(l) + CO2(g)

1(ii). For each reaction equation, identify the driving force of the reaction

2. What is an electrolyte? How can you experimentally differentiate between a weak electrolyte and a strong electrolyte? Name and give the formulas of a strong electrolyte and a weak electrolyte.

3. 2.516 g of a compound containing carbon, hydrogen and oxygen (CXHYOZ) is subjected to combustion analysis. The results show that 3.082 g of CO2 and 2.705 g of H2O were produced.

(i). What is the empirical formula for the compound?

(ii). If the molecular weight of the compound is 160.2 g/mol, what is the molecular formula of the compound?

4. Consider the reaction of aluminum and oxygen:

Al(s) + O2(g) ® Al2O3(s)

(i). Which is the limiting reactant if we start with 30.0 g Al and 30.0 g O2?

(ii). What is the Theoretical Yield for the reaction?

(iii). If 25.85 g of Al2O3 was collected at the completion of the

reaction (actual yield), what is the % yield for the reaction?

5. (a). A 1.506-g sample of limestone-containing material gave 0.558 g of CO2, in addition to CaO, after being heated at a high temperature. What was the mass percent of limestone (CaCO3) in the original sample?

CaCO3(s) → CaO(s) + CO2(g)

H2SO4 (aq) +

CaCO3 (s) ®

H2O (l)

+ CO2(g)

+ CaSO4(s)

5 (b). How many grams of calcium carbonate can be consumed by 45.5 mL of 0.125 M H2SO4 (aq)?

6. What volume of 0.600 M HC2H3O2, acetic acid, is required to neutralize 25.0 mL of 0.175 M Ca(OH)2?

2 HC2H3O2 + Ca(OH)2 ® Ca(C2H3O2)2 + 2H2O

What mass of pure acetic acid is required?

Answer 1

1(i). Balance the following equations, and then write the net ionic equation

(a) (NH4)2CO3(aq) + Cu(NO3)2(aq) → CuCO3(s) + 2NH4NO3(aq) is the balanced equation

Net ionic equation is

Cu+2(aq) + CO3-2(aq) ---------> CuCO3(s)

(b) Mg(OH)2(s) +2 HCl(aq) → MgCl2(aq) + 2H2O(l) is th ebalanced equation

2H+ (aq) + 2OH-(aq) -------------> 2H2O(l) is the net ionic equation

(c) BaCO3(s) +2 HBr(aq) → BaBr2(aq) + H2O(l) + CO2(g) is the balanced equation

2H+ (aq) + CO3-2(aq) ------> H2O(l) + CO2(g) is the net ionic equation

1(ii). For each reaction equation, identify the driving force of the reaction

For reaction a , the precipitation

for reaction b ,(acid-base neutralization) the driving force is formation of water from ions.

for reaction c , the formation of water and a gas formation are the driving forces.

Q2)An electrolyte is a substance that conducts electricity either in molten/fused state or in aqueous solution and thus decomposes to give component species.

In genral all electrolytes dissolve in water and produce the corresponding ions.

AB (aq) ------> A+ + B-

A strong electrolyte is the one that dissociates completely and conducts more electricity

NaCl (aq) -------------> Na+ + Cl-

other examples are HCl, HNO3, K2So4 etc.

A weak electrolyte is the one that dissociates to small extent into ions and conducts small amount of electricity.

NH4OH(aq) <------> NH4+ + OH-

other examples are acetic acid,(CH3COOH) , HCn etc.