WAEC Chemistry Past Questions & Answers - Page 180

896.

The key factor to be considered in siting a chemical industry is

A.

favourable climatic conditions

B.

the availability of space to store raw materials

C.

its nearness to other industrial establishments

D.

its nearness to the source of raw materials

Correct answer is D

No explanation has been provided for this answer.

897.

What is the change in the oxidation number of 1- in the reaction represented by the following equation? 51 -1(aq) + 6H+(aq) + 1O-3(aq) → 312(g) + 3H2O(l)

A.

-5 to -3

B.

-1 to 0

C.

+ 5 to + 0

D.

-1 to + 2

Correct answer is B

No explanation has been provided for this answer.

898.

Which of the following statements is true of an endothermic reaction? I. Heat is absorbed from the surrounding II. The heat content of the products is more than that of the reactants III. The enthalpy change is positive IV. The surrounding is at a lower temperature than the system.

A.

l only

B.

l and ll only

C.

l,ll and lll only

D.

l, ll, lll and lV

Correct answer is C

For an endothermic reaction; heat flows from the surroundings to the system( but that doesn't make the surroundings to be at a lower temperature than the system) meaning the surroundings are at a higher temperature than the system. The system's enthalpy change, i.e. ΔH is positive or > 0. The heat content of the product is more than that of the reactant.

899.

The condensation of several amino acid molecules gives

A.

long chain alkanoic acids

B.

secondary alkanols

C.

alkanoates

D.

proteins

Correct answer is D

No explanation has been provided for this answer.

900.

When ammonium trioxocarbonate (IV) solution is added to separate solutions of calcium, zinc and sodium salt precipitate could be formed in the case of

A.

calcium only

B.

zinc only

C.

calcium and znic only

D.

sodium and zinc only

Correct answer is C

No explanation has been provided for this answer.