Inorganic Chemistry - P8 [Ways and Means of Expressing Concentrations] ]

Concentration

______ - is the ratio of the solute over the volume of the solution

• mole of solute

• mass of solute

Units used for SOLUTE

• Liter (L)

• Kilogram (kg)

Units used for SOLUTION

c. 285.48 g

1. How many grams of water must be added to 200mL of NaOH solution in order to have a solution with a specific gravity of

1.157, 13.55%? (Specific gravity of NaOH = 1.32, 28.83%)

a. 492.85 g

b. 294.95 g

c. 285.48 g

d. 258.45 g

a. 0.0200 N

2. If 40mL of 0.100M KMnO4 (acidified) is diluted with 160mL of water, then the normality of the resulting solution will be

a. 0.0200 N

b. 0.0250 N

c. 0.1000 N

d. 0.1250 N

b. 8 g

3. How many grams of NaOH is dissolved in 200 mL of a 1 M solution? (Atomic weights: Na = 23, O = 16, H = 1)

a. 1 g

b. 8 g

c. 40 g

d. 200 g

b. Number of moles of NaOH

4. A 100mL solution contains 4g of NaOH. If 50mL of water is added to this solution, which of the following will remain

unchanged?

a. Molarity of the solution

b. Number of moles of NaOH

c. Percent by weight of NaOH

d. Normality of the solution

b. 12.4

NOTE:

• The solution is basic, so reject A.

• The answer is related to the rejected value. In this case, 14 – 1.6 = 12.4

5. What is the pH of this sample? . A sample of 0.025 M KOH stands at 250C, where 10^0.4  2.5

a. 1.6

b. 12.4

c. 13

d. 13.6

a. 1.6

5. What is the pOH of this sample? . A sample of 0.025 M KOH stands at 250C, where 10^0.4  2.5

a. 1.6

b. 12.4

c. 13

d. 13.6

c. 50 mL

7. What volume of 0.2 M NaOH is needed to neutralize 25 mL of 0.2 M H2SO4?

a. 12.5 mL

b. 25 mL

c. 50 mL

d. 100 mL

c. 0.1793 N

8. What is the normality of an acid solution if 40 mL of the solution requires 38.16 mL of 0.1879 N alkali for neutralization?

a. 0.4000 N

b. 0.2678 N

c. 0.1793 N

d. 0.1274 N

b. 1 N NH₄OH

9. Which of the following solutions has molarity different from the rest?

a. 6 N H₃PO₄

b. 1 N NH₄OH

c. 2 N HC₂H3O₂

d. 4 N Ca(OH)₂