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.

2,091.

50cm 3 of a saturated solution of potassium trioxonitrate (V)at 40°C contains 5.05g of the salt. What is the solubility of potassium trioxonitrate (V) at 40°C? (KNO3 = 101)

A.

1.0 mol dm-3

B.

1.5 mol dm-3

C.

2.0 mol dm-3

D.

2.5mol dm-3

E.

5.0mol dm-3

Correct answer is A

No explanation has been provided for this answer.

2,092.

Which of the following is a condition for a spontaneous reaction?

A.

∆H -T is zero

B.

∆H-T∆ S is positive

C.

∆H-T∆ S is negative

D.

∆S is zero

E.

∆S is positive

Correct answer is C

No explanation has been provided for this answer.

2,093.

The electronic configuration of two atoms X and Y are as follows: X - 1s 2 2s 22p 63s 1, Y -1s 22s 22p 63s23p 64s 2 which of the statements below is true of the position of X and Y in the Periodic Table?

A.

x belongs to group 1, Y belongs to period 2,

B.

x belongs to group 1, Y belongs to period 4

C.

x belongs to group 2, Y belongs to period 1

D.

x belongs to group 3, Y belongs to period 2

E.

x belongs to group 3, Y belongs to period 4

Correct answer is B

No explanation has been provided for this answer.

2,094.

What quantity of copper will be deposited by the same quantity of electricity that deposited 9.0g of aluminum? (A = 27, Cu = 64)

A.

64g

B.

32g

C.

7.1g

D.

6.4g

E.

3.2g

Correct answer is B

Al has valency of 3+:

3F will deposit 27g

xF will deposit 9g

cross multiply → \(\frac{9g * 3F}{27g}\)

: 1F = 9g

Cu has valency of 2+:

2F will deposit 64g

1F will deposit xg

cross multiply → \(\frac{64g * 1F}{2F}\)

: 1F = 32g

2,095.

Which of the following statements is not true of tin? it

A.

is a p-block element

B.

is extracted from cassiterite SnO 2

C.

is used for protecting iron containers from corrosion

D.

combines with copper to form the alloy brass

E.

shows two oxidation states, + 2 and + 4 in most of its compounds

Correct answer is D

No explanation has been provided for this answer.