JAMB Chemistry Past Questions & Answers - Page 292

1,456.

If 100 cm3 of oxygen pass through a porous plug in 50 seconds, the time taken for the same volume of hydrogen to pass through the same porous plug is?



(O = 16, H = 1)

A.

10.0 s

B.

12.5 s

C.

17.7 s

D.

32.0 s

Correct answer is B

100 cm3 of O2 diffuse 50 sec
∴ 100 cm3 of H2 → (100) / (100) x (50) /(1)
t1 50 sec
molecular mass H+ → 2 x 1 = 2
molecular mass of O2 16 x 2 = 32

T2 = t1 √M2/M1 = t2 = 50 √2/32

50√0.625 = 50 x 0.25 = 12.5 secs

1,457.

Which of the following is a measure of the average kinetic energy of the molecules of a substance?

A.

Volume

B.

Mass

C.

pressure from age grades

D.

Temperature

Correct answer is D

No explanation has been provided for this answer.

1,458.

A given mass of gas occupies 2 dm3 at 300k. At what temperature will its volume be doubled keeping the pressure constant?

A.

400 k

B.

480 k

C.

550 k

D.

600 k

Correct answer is D

No explanation has been provided for this answer.

1,459.

wH2SO4 + xAI(OH)3 → yH2O + = zAI2(SO4)3. The respective values of w.x.y and z in the equation above are?

A.

2,2,5 and 1

B.

3,2,5 and 2

C.

3,2,6 and 1

D.

2,2,6 and 2

Correct answer is C

No explanation has been provided for this answer.

1,460.

How many moles of (H+) are there in 1 dm3 of 0.5 M solution of H2SO4?

A.

2.0 moles

B.

1.0 moles

C.

0.5 mole

D.

0.25 mole

Correct answer is B

mole = (M x V ) / (1000cm3) = (0.5 x 1000cm3) = 0.5 moles
For H2SO4 → 2H+SO42-
1 mole of H+ = 0.5 moles
2H+ = 2 x 0.5 mole = 1.0 mole