Chapter 1

Question 1

What is Brownian movement?

Answer 1

Particles of liquid/gas moving randomly in all directions, colliding with each other

Question 2

What is diffusion?

Answer 2

Movement of particles from a region of higher concentration to lower concentration, resulting in even spreading

Question 3

How to calculate molar mass?

Answer 3

Atomic mass of element 1+ atomic mass of element 2
Ex- find the molar mass of HCl
Atomic mass of hydrogen =1
Atomic mass of Cl= 35.5
1+35.5=36.5

Question 4

What is the difference between boiling and evaporation?

Answer 4

Boiling occurs throughout the liquid, while evaporation is a surface phenomenon only. You can use vapourisation to depict both

Question 5

Describe the effect of impurities on the boiling point and melting point of a substance. Give an example.

Answer 5

Impurities increase the boiling point and decrease the melting point. They also increase density. Roadside vendors don’t use freezers, instead they use boxes filled with ice and salt. Salt is an impurity. Cryolite (an impurity) is added to aluminium oxide to save power during extraction of aluminium.