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.

1,211.

What is the expression for the equilibrium constant (Kc) for the following reaction? N2(g) + O2(g) ⇌ 2NO(g)

A.

\(\frac{[NO^2]}{[N^2] + [O^2]}\)

B.

\(\frac{[2NO]^2}{[N_2][O_2]}\)

C.

\(\frac{[N_2] + [O_2]}{2[NO]^2}\)

D.

\(\frac{[NO]^2}{[N_2][O^2]}\)

Correct answer is D

No explanation has been provided for this answer.

1,212.

What will happen if more heat is applied to the following system at equilibrium?

X\(_2\)(g) + 3Y\(_2\)(g) ⇌ 2XY\(_3\)(g); ∆H = xKJmol\(^{-1}\)

A.

the yield of XY 3 will decompose

B.

more of XY3 will decompose

C.

More of X2 will react

D.

the forward reaction will remain static

Correct answer is C

Increase in temperature will cause the forward reaction to occur, increasing the amounts of the products and decreasing the amounts of reactants.

1,213.

Which of the following salt solutions will have a pH greater than 7?

A.

NaCI(aq)

B.

Na2CO3(aq)

C.

Na2SO4(aq)

D.

NaHSO4(aq)

Correct answer is B

No explanation has been provided for this answer.

1,214.

Calculate the mass of sodium hydroxide in 5.00 dm3 of a 0.125 mol dm-3 solution. [NaOH = 40 g mol-1]

A.

0.0156 g

B.

0.625 g

C.

1.00 g

D.

25.0 g

Correct answer is D

1 mole of NaOH per dm3 has a mass of 40g.
mass of NaOH in 0.125mole
= 0.125 x 40 = 5g.
mass in 5.00 dm3 of the solution.
= 5 x 5 = 25.0g.

1,215.

Which of the following substances increases in mass when heated in air?

A.

Sodium chloride

B.

lodine crystals

C.

Magnesium ribbon

D.

Copper (ll) oxide

Correct answer is C

No explanation has been provided for this answer.