Chemistry Lecture-2

Topics

1) Laws of chemical combinations

2) The Gas Laws

3) Ideal Gas Equation

4) Avogadro’s Hypothesis

5) Vapour density

6) Mole concept

7) What is a Solution?

1) Laws of chemical combinations

Questions

1. If water sample are taken from sea, rivers or lake, they will be found to contain hydrogen

and oxygen in the approximate ratio of 1 : 8. This indicates the law of:

(a) Multiple proportion (b) Definite proportion

(c) Reciprocal proportions (d) None of these

2. Hydrogen and oxygen combine to form H2O2 and H2O containing 5.93% and 11.2%

hydrogen respectively. The data illustrates :

(a) law of conservation of mass (b) law of constant proportion

(c) law of reciprocal proportion (d) law of multiple proportion

The of Reciprocal Proportions

The Gas Laws

Ideal Gas Equation

Avogadro’s Hypothesis

Vapour density (V.D.)

Molecular weight and Equivalent weight

Concept of Acidity and Basicity

What is a Solution?

Mole concept

1) Strength of the solution (gm/ml)

2) Mass Percentage (%w/w)

3) Molarity (M)

4) Normality (N)

5) Relation between Molarity and Normality

6) Molality (m)

7) Mole Fraction (X)

1) Strength of the solution (gm/l)

and Specific gravity(density) of the solution (gm/ml)

Que: 6 grams of a solute are present in 500 ml of solution.

What is the strength and the density of the solution?

2) Mass Percentage (%w/w)

Que: A solution is prepared by adding 10 gm of a

substance S to 50 gm of water. Calculate the %w/w of

the solute.

3) Molarity (M)

Que: 49 grams of H2SO4 are present in 100 ml aqueous solution.

What is the molarity of H2SO4. Molar mass of H2SO4 = 98gm/mol

4) Normality (N)

Que: Calculate the normality (N) of the solution containing 5 g

NaOH dissolved in 250 mL aqueous solution.

5) Relation between Molarity and Normality

Que: Calculate the Normality (N) of 0.3 M H2SO4 solution.

6) Molality (m)

Que: 214.2 g of an aqueous solution of sugar contains 34.2

grams sugar. If molecular mass of sugar is 342, calculate the

molality of the solution.

7) Mole Fraction (X)

Que: Calculate the mole fraction of water in a mixture of 12g

water, 108g acetic acid and 92g ethanol. Molar mass of H2O,

CH3COOH and C2H5OH is 18, 60 and 46 respectively.