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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.

236.

The 25°C evaporation of a 100 cm3 solution of K2CO3 to dryness gave 14g of the salt. What is the solubility of K2CO3 at 25°C? [K2CO3 = 138]

A.

0.01 mol dm3

B.

0.101 mol dm3

C.

1.01 mol dm 3

D.

10.0 mol dm3

Correct answer is C

solubility( in mol/dm^3) = massofsaltMolarMassofsalt=1000cm3volumeofsolutionincm3

                                         14138=1000cm3100

                                           1400013800=1.01mol/dm3

237.

The Bohr model of the atom proposed the existence of? 

A.

the nucleus

B.

electron shells

C.

nucleons

D.

neutrons

Correct answer is B

Bohr Model is a planetary model in which the negatively charged electrons orbit a small, positively charged nucleus similar to the planets .

238.

How many coulombs of electricity would liberate 1.08g of Ag from a solution of silver salt?

[Ag = 108.0; 1F = 96500 C]

A.

96500 C

B.

9650 C

C.

965 C

D.

9.65 C

Correct answer is C

No explanation has been provided for this answer.

239.

The reactivity of fluorine is high because of 

A.

its high electronegativity

B.

the small size of the fluorine atom

C.

the availability of d-orbitals

D.

the strong F-F bond

Correct answer is A

No explanation has been provided for this answer.

240.

Which of the following statements about Group VII elements is correct?

A.

they are present in the same physical state

B.

they are strong reducing agents

C.

their reactivity decreases down the group

D.

they exist as monoatomic molecules

Correct answer is C

No explanation has been provided for this answer.