WAEC Chemistry Past Questions & Answers - Page 198

986.

The gas given off when NH4Cl is heated with an alkali is

A.

H2

B.

CI2

C.

N 2

D.

NH 3

Correct answer is D

No explanation has been provided for this answer.

987.

What volume of hydrogen will be produced if 100cm3 of ammonia is completely decomposed at constant temperature and pressure? The equation for the reaction is 2NH3(g) → N2(g) + 3H2(g)

A.

50cm3

B.

150cm3

C.

200cm3

D.

300cm3

Correct answer is B

According to the equation 2NH3 → N2 + 3H2 2x22400cm 3 of ammonia will produce 3x22400cm 3 of hydrogen if 100cm3 of NH3 is used H2 volume = 100/2x22400 x 3 x22400 = 150cm3

988.

Which of the following decreases when a given mass of gas is compressed to half its initial volume?

A.

Average intermolecular distance

B.

Frequency of collisions

C.

Number of molecules present

D.

Atomic radius of each particle

Correct answer is A

No explanation has been provided for this answer.

989.

If a metal R forms a compound with the formula R(NO3)2 the formula of its tetraoxosulphate (VI) is

A.

R(SO4)2

B.

RSO4

C.

R2SO4

D.

R2(SO4)3

Correct answer is B

No explanation has been provided for this answer.

990.

The conclusion from Rutherford's from radioactive substance alpha-scattering experiment is that

A.

atoms are mostly empty space with a samll

B.

emissions from radioactive substances consist of three main components

C.

there is unclear pull on orbital electrons

D.

electrons are deflected by both magnetic and electric fields

Correct answer is A

No explanation has been provided for this answer.