JAMB Chemistry Past Questions & Answers - Page 292

1,456.

Two atoms represented as U and U are?

A.

isomers

B.

allotropes

C.

isotopes

D.

anomers

Correct answer is C

No explanation has been provided for this answer.

1,457.

An element, E, has the electronic configuration 1s22s22p63s2p3. The reaction of E with a halogen X can give?

A.

EX3 and EX5

B.

EX3 only

C.

EX5 only

D.

EX2 and EX3

Correct answer is A

No explanation has been provided for this answer.

1,458.

For iodine crystals to sublime on heating, the molecules must acquire energy that is?

A.

less than the forces odf attraction in the solid

B.

equal to the forces of attraction in th solid

C.

necessary to melt the solid

D.

greater than the forces of attraction in both the solid and the liquid phases

Correct answer is D

No explanation has been provided for this answer.

1,459.

How many moles of oxygen molecules would be produced from the decomposition of 2.50 moles of potassium trioxochlorate (V)?

A.

2.50

B.

3.50

C.

3.75

D.

7.50

Correct answer is C

2KClO3(s) → 2KCl(s) + 3O2(g)
From the above balanced equation, 2 moles of reactant decomposed to give 3 moles of O2 i.e.
i mole of reactant will produce (3)/(2) moles O2.
∴ 2.5 moles KClO3 will give
= 3.75 moles

1,460.

A balanced chemical equation obeys the law of?

A.

conservation of mass

B.

difinite proportions

C.

multiple proportions

D.

conservation of energy

Correct answer is A

No explanation has been provided for this answer.