Which of the following is an example of a mixture?

A. Common salt

B. Blood

C. Sand

D. Washing soda

Calculate the percentage by mass of nitrogen in calcium trioxonitrate (V)
[Ca = 40, N = 14, O = 16]

A. 8.5%

B. 13.1%

C. 17.1%

D. 27.6%

The droplets of water observed around a bottle of milk taken out of the refrigerator is due to the fact that the?

A. water vapour in the air around the bottle gains some energy from the bottle

B. temperature of the milk drops as it loses heat into the surroundings

C. saturated vapour pressure of the milk is equal to the atmospheric pressure

D. water vapour in the air around the bottle loses some of its energy to the bottle

The volume of a given gas is V cm3 P mm Hg. what is the new volume of the gas if the pressure is reduced to half at constant temperature?

A. 4 V cm³

B. 2 V cm³

C. V/2 cm³

D. V cm³

Moving from left to right across a period, the general rise in the first ionization energy can be attributed to the?

A. decrease in nuclear charge

B. increase in nuclear charge

C. decrease in screening effect

D. increase in screening effect

How many unpaired electron(s) are there in the nitrogen sub-levels?

A. 3

B. 2

C. 1

D. none

The stability of the noble gases is due to the fact that they?

A. have no electron in their outermost shells

B. have duplet or octet electron configurations

C. belong to group zero of the periodic table

D. are volatile in nature

The maximum number of electrons in the L shell of an atom is?

A. 2

B. 8

C. 18

D. 32

Elements in the same period in the periodic table have the same?

A. number of shells

B. atomic number

C. chemical properties

D. physical properties

12D + 13T → 24He + 01n + energy
The reaction above illustrates?

A. alpha decay

B. artificial transmutation

C. nuclear fussion

D. nuclear fission