Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

786.

The general gas equation was deprived from______?

A.

Boyle's and Gay Lussac's laws

B.

Boyle's and Graham's laws

C.

Boyle's and Charles' laws

D.

Dalton's atomic theory

Correct answer is C

No explanation has been provided for this answer.

787.

Consider the following reaction equation:
SO42-(aq) + 2H+(aq) + ye- \(\to\) SO42-(aq) + H2O(1).

The value of y in the equation is

A.

2

B.

3

C.

4

D.

6

Correct answer is A

From the reaction, the total charge on the left side = The total charge on the right side

-2 + 2 + y = -2 : y = -2 : y = 2

788.

The number of oxygen molecules present in 16.0g of the gas is ______?
[Avogadro's number = 6.02 x 1023]

A.

6.02 x 1022

B.

6.02 x 1023

C.

3.01 x 1023

D.

1.51 x 1023

Correct answer is C

1 mole = Molar mass of gas = Avogadros number
32g of O2 = 6.02 x 1023
16g of O2 = x
x = \(\frac{16 \times 6.02 \times 10^23}{32}\) = 3.01 x 1023

789.

Consider the following reaction equation:
C2H4(g) + 3O2(g) \(\to\) 2CO2(g) + 2H2O(g)

The volume of CO2(g) produced at s.t.p when 0.05 moles of C2H4(g) was burnt in O2(g) is
[Molar Volume of gas = 22.4dm3

A.

1.12dm3

B.

2.24dm3

C.

3.72dm3

D.

4.48dm3

Correct answer is B

\(\frac{\text{volume}}{\text{molar volume}}\) = 0.05

1 mole of ethane produces 2 moles of carbon(iv)oxide

∴ 0.05  mole of ethane will produce x moles of carbon(iv)oxide

= \(\frac{\text{volume}}{22.4}\) = 0.05 X 2 X 22.4 =  2.24dm\(_3\)

790.

Which of the following trioxonitrate(V) salts would decompose on heating to form a metal?

A.

Cu(NO3)2

B.

AgNO3

C.

Pb(NO3)2

D.

KNO3

Correct answer is B

No explanation has been provided for this answer.