A mole does not signify

1

(a)

atomic mass unit

(b)

6.023 x 10²³ ions

(c)

22.4 litres of a gas at STP

(d)

gram molecular mass

Which one of the following compound is not made up of charged ions?

1

(a)

HCl

(b)

NaCl

(c)

MgCl₂

(d)

CaO

A group of ....... atoms, molecules or ions is called one mole.

1

(a)

6.022 x 10²³

The unit of atomic mass is .............

1

(a)

u

One mole of S contains ............ atoms.

1

(a)

8 x 6.022 x 10²³

Which postulate of Dalton's atomic theory is the result of the law of conservation of mass?

1

(a)

What is the present accepted or IUPAC (International Union Pure and Applied Chemistry) system of symbols of elements?

2

(a)

Write the names and symbols of five elements where the symbols are taken from their name in English.

2

(a)

The drawbacks of Dalton's atomic theory of matter.

3

(a)

What is the utility of the mole concept?

3

(a)

How were the names of elements derived?

4

(a)

What is molecular formula? Explain with example what information can be derived from a molecular formula?

4

(a)

Verify by calculating that
(i) 5 moles of CO₂ and 5 moles of H₂O do not have the same mass.Atomic mass of carbon, oxygen and hydrogen are 12 u, 16 u, 14 u respectively.
(ii) 240 g of calcium and 240 g magnesium elements have a mole number ratio of 3 : 5.Atomic mass of calcium and magnesium are 40 u and 24 u respectively.

5

(a)