Analytical Chemistry

CHM 256: BASIC ANALYTICAL CHEMISTRY
TUTORIAL 1: INTRODUCTION: ANALYTICAL CHEMISTRY

1. What is chemical analysis?
2. Differentiate between qualitative and quantitative analysis (Oct 2008, 2009, Dec 2009, Apr
2010)
3. Give 7 steps in performing any chemical analysis (Apr 2010)
4. Briefly explain how to prepare the following solutions:
a) 1.0 L 10.50 % (w/v) aqueous CH3CH2CH2OH (answer : 105 g) (Oct 2006, Oct 2007,
Oct 2008)
b) 500 mL 2.0 M H2SO4 from a commercial reagent, at 90% (w/w) purity and specific gravity of 1.84. (answer : 59.18 mL) (Oct 2007)
c) 250 mL 50 ppm of AgNO3 from the solid chemical (answer : 0.0125 g)
d) 500 mL 6.5% (w/v) aqueous ethanol (answer : 32.5 g)
e) 0.1 L 6.0 M H3PO4 from a commercial reagent, at 85% (w/w) purity and specific gravity of 1.69 (answer : 40.95 mL) (Oct 2008)
f)

400 mL 0.080 M of AgNO3 from the solid chemical (answer : 5.44g)
+

g) 500 mL 100 ppm Ag from pure reagent solid silver nitrate (answer : 0.05 g) (Oct 2006
& Oct 2007)
6. The density of commercial concentrated HNO3 is 1.41 g/mL. The concentrated acid contains
69% (wt/wt) of pure acid. Determine:
a) the quantity in gram of pure HNO3 in 1000 mL of the concentrated HNO3(answer :
972.9 g)
b) the molarity of the commercial concentrated acid (answer : 15.44 M)
c) the volume (in mL) of concentrated acid needed to prepare 500 mL 0f 2.50 M HNO 3 solution (answer : 80.96 mL)
d) How mililiters of KOH solution, prepared by dissolving 60.0 g of KOH in 100 mL of solution, are needed to prepare 450 mL of a 0.70 M solution (answer : 29.41 mL)
7. A student wishes to prepare 500 mL of 25 ppm solution of barium. Calculate:
a) How many mililiters of 1000 ppm barium would be required if he/she were to prepare this by dilution? (answer : 12.5 mL)
b) If he/she were to prepare this from pure solid BaCl2.2H2O, how many grams would be required? (answer : 22.4 mg)
8. Tell how you would prepare 250 mL of a 5.00 M solution of H3PO4 from its commercial reagent
(purity of 85% w/w with specific gravity of 1.69) (answer : 85.27 mL)
9. The density of concentrated HCl is 1.19 g/mL. This concentrated acid contains 36% (w/w) pure acid. Calculate:
a) the number of grams of pure HCl in 1.0 L the concentrated HCl (answer: 428.4 g/L)
b) the molarity of concentrated acid (answer: 11.74 M)
c) the volume of concentrated acid needed to prepare 2.0 L of 0.1 M HCl solution(answer: 17.04 mL)

CHM 256: BASIC ANALYTICAL CHEMISTRY
TUTORIAL 1: INTRODUCTION: ANALYTICAL CHEMISTRY

10. Methanol, CH3OH has a density of 0.79 g/mL. If 26.5 mL of methanol is added to water to make a 250.0 mL solution, calculate the concentration of methanol solution in,
a) % v/v (answer: 10.6%)
b) % w/v (answer: 8.4%)
c) Molarity (answer: 2.62 M)
11. Describe the preparation of a 250 mL solution containing of 1000 ppm Cu

2+

stating from solid

CuSO4.5H2O (MW=249.5). (answer: 0.982 g)
12. List and explain all the steps involved in preparing 1.00 L 0.003 M standard solution Na 2CO3 standard solution. (answer: 0.318 g)
13. Calculate the molar concentration of ethanol in aqueous solution that cantains 2.3 g of
C2H5OH in 3.50 L of solution (answer: 0.0413 M)
14. Describe the preparation of 2.00 L of 0.108 M BaCl2 from BaCl2.2H2O (answer: 52.8 g)
-

15. Describe the preparation of 500 mL of 0.0740 M Cl solution from solid BaCl2.2H2O (answer:
4.52 g)
16. Calculate the molar concentration of HNO3 in a solution that has a specific gravity of 1.42 and is 70.5% HNO3 (w/w). (answer: 16 M)
+

22

17. How many Na ions are contained in 5.43 g of Na3PO4? (answer: 5.98 x 10

+

Na ions)

18. Find the number of moles of the indicated species
a. 4.96 g of B2O3 (answer: 0.0712 mol)
-4

b. 333 mg of Na2B4O7.10H2O (answer: 8.73 x 10 mol)
c. 8.75 g of Mn3O4 (answer: 0.0382 mol)
-3

d. 167.2 mg of CaC2O4 (answer: 1.31 x 10 mol)
19. Find the number of milimoles of solute in:
-3

a. 2.00 L of 3.25 x 10 M KMnO4 (answer: 6.5 mmol)
b. 750 mL of 0.0555 M KSCN (answer: 41.6 mmol)
-3

c. 250 mL of a solution that contains 5.41 ppm of CuSO4 (answer: 8.47 x 10 mmol)
d. 3.5 L of 0.333 M KCl (answer: 1165.6 mmol)
20. What is the mass in milligrams of:
4

a. 0.777 mol of HNO3 (answer: 4.90 x 10 mg)
4

b. 500 mmol of MgO (answer: 2.015 x 10 mg)
6

c. 22.5 mol of NH4NO3 (answer: 1.80 x 10 mg)
6

d. 4.32 mol of (NH4)2Ce(NO3)6 (548.23g/mol) (answer: 2.37 x 10 mg)