Question

1) a) Select the correct option:

i) When temperature is increased kinetic energy of molecules:
(1) remains same
(3) decrease
(2) increases
(4) first increases then decreases

ii) Boiling point is temperature at which liquid:
(1) changes into solid
(3) changes into liquid
(2) changes into vapour
(4) none of these

iii) The formula of phosphorus molecule is:
(1) P₂
(3) P.
(2) Ps
(4) Ps

iv) The valencies of cuprous and cupric ions are:
(1) +1 and +2
(3) +3 and +4
(2) +2 and +3
(4) I and +3

v) How many valence electrons does an atom of sodium have?
(1) 1
(3) 3
(2) 2
(4) 4​

Answer 1

Answer:

i) 2 ,ii) 2 , iii ) P4 ,iv) 1 , v ) 1

Explanation:

1) Gay Lussac's law states that at constant volume, pressure of a fixed amount of a gas varies directly with the temperature.

∴P∝T (at constant volume)

Thus, if temperature is increased at constant volume pressure increases.

2) The temperature at which liquid changes into vapour is called its boiling point. The boiling point of water is 100 °

C. It is dependent on atmospheric pressure.

3) The image is of a ball-and-stick model of white phosphorus. It has a tetrahedral shape and has the formula P4. The two main forms of phosphorus are white phosphorus and red phosphorus

4) The valency of cuprous is 1 and the valency of cupric is 2.

5) Sodium has one valence electron. Valence electrons are electrons found in the outermost shell of an atom.