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SK0013 PHYSICAL CHEMISTRY – TUTORIAL 2
MATTER II
1. Given the formula K2CO3, determine the percent composition (fraction of K, C and O) of potassium carbonate (K2CO3 = 138.205 g/mol).
2. A compound has the following composition: C=40%, H=6.67%, O=53.3%. Its molecular weight is 60.0. Derive its molecular weight.
3. Determine the molar concentration of each of the following solutions:
a) 166 g KI per L solution
b) 33.0 g (NH4)2SO4 in 200 mL solution
c) 12.5 g CuSO4.5H2O in 100 mL solution
d) 10.0 mg AL3+ per mL solution
4. The equation for the reaction of sucrose (sugar) with oxygen is
C12H22O11 + 12O2
12CO2 + 11H2O
How many g of CO2 is produced per g of sucrose used? How many mol of oxygen gas is needed to react with 1.0 g sucrose?(C12H22O11= 342 g/mol )
5. The reaction 2Al + 3MnO
Al2O3 + 3Mn proceeds until limiting substance is all consumed. A mixture containing 110 g Al and 200 g MnO was heated to initiate the reaction. Which initial substance remained in excess, and by how much?
6. What is the oxidation number of sulphur in each of the following cases?
a) S2b) H2SO4
c) S2O32d) CS2
e) S8
7. To prepare 100 g of 19.7% by weight solution of NaOH, how many grams each of
NaOH and H2O are needed?
8. Balance the following equations:
a) Fe2(SO4)3 + BaCl2
b) Ba(OH)2 + HCl
c) BaSO4 + CuCl2
d) Zn + H2SO4
9. Balance the following skeleton reactions and identify the oxidizing and reducing agents (ion-electron method).
MnO4 (aq) + H2O2(aq)
Mn2+(aq) + O2(g)