25cm³ of a gas X contains Z molecules at 15^oC and 75 mmHg. How many molecules will 25 cm³ of another gas Y contain at the same temperature and pressure?

A. 2 Y

B. 2 Z

C. Z

D. Y

What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?
[H = 1, O = 16]

A. 36.0g

B. 8.0g

C. 72.0g

D. 16.0g

A particle that contains 9 protons, 10 neutrons and 10 electrons is a

A. negative ion

B. positive ion

C. neutral atom of non-metal

D. neutral atom of a metal

Cancerous growths are cured by exposure to

A. γ - rays

B. β - rays

C. α - rays

D. infrared rays

An oxide XO₂ has a vapour density of 32. What is the atomic mass of X?

A. 32

B. 20

C. 14

D. 12

Millikan's contributions to the development of atomic theory is the determination of

A. charge on electron

B. positive rays

C. charge to mass ratio

D. cathode rays

Four elements W, X, Y and Z have atomic number 2,6,16 and 20 respectively. Which of these elements is a metal?

A. X

B. W

C. Z

D. Y

An elements X with relative atomic mass 16.2 contains two isotopes ¹⁶₈X with relative abundance of 90% and ^m₈X with relative abundance of 10%. The value of m is

A. 16

B. 18

C. 12

D. 14

Which of the following statements is correct about the average kinetic energy of the molecules of a gas?

A. It increase with increase in pressure

B. It increase at constant temperature

C. It increase with increase in temperature

D. It increase with increase in volume

The pollution from petroleum spillage in rivers and lakes can best be dispersed by

A. Pouring detergents

B. Passing of ships through the area

C. Pouring organic solvents

D. Evaporation