Cathode rays causes an object placed behind a perforated anode to cast a shadow on the screen. This observation shows that the rays?
- A. are positively charged
- B. are negatively charged
- C. have mass
- D. travel in straight lines
If an atom is represented as \( _{11}^{23}X \), which of the following deduction is correct?
- A. it contains 12 protons
- B. it forms a covalent chloride
- C. its atomic number is 23
- D. it is an alkali metal
The basic assumption in the kinetic theory of gases that the collisions of the gaseous molecules are perfectly elastic implies that the?
- A. forces of attraction and repulsion are in equilibrium
- B. gaseous molecules can occupy any available space
- C. gaseous molecules will continue their motion indefinitely
- D. gases can be compressed
A gas exerts pressure on its container because?
- A. the molecules of a gas collide with the walls of the container
- B. some of the molecules are moving faster than others
- C. of the collisions of the molecules with each other
- D. of the mass of the molecules of the gas
0.0075 mole of calcium trioxocarbonate (IV) is added to 0.015 mole of a solution of hydrochloric acid. The volume of gas evolved at s.t.p is?
[Molar volume of a gas at s.t.p = 22.4 dm3]
- A. 224cm3
- B. 168cm3
- C. 112cm3
- D. 100cm3
The percentage of water of crystallization in ZnSO\(_4\).7H\(_2\)O is?
[Zn = 65, S = 32, O = 16, H = 1]
- A. 33%
- B. 44%
- C. 55%
- D. 87%
Which of the following is a physical change?
- A. Freezing ice cream
- B. dissolving calcium in water
- C. burning kerosene
- D. Exposing white phosphorus to air
A mixture of sugar and sulphur can be separated by?
- A. dissolution in water, evapouration and filtration
- B. filtration, evaporation and dissolution in water
- C. dissolution in water, filtration and evaporation
- D. evaporation, dissolution in water and filtration