JAMB Past Questions and Answers - Page 1309

6,541.

The use of a three-column cash book is determine by?

A.

Cash discounts

B.

Trade discounts

C.

Cash transactions

D.

Bank transactions

Correct answer is A

No explanation has been provided for this answer.

6,542.

The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is – (Ag = 108 F = 96500(mol-1)

A.

54.0g

B.

27.0g

C.

13.5g

D.

108.0gQ

Correct answer is A

Recall that

mass deposited = \(\frac{MmIt}{96500n}\)

Mm =108, t = 4830s

I = 10A, n = 1

m = 108 × 10 × (\(\frac{4830}{96500}\)) × 1

m = 54.0g

6,543.

The shape of ammonia molecules is

A.

trigonal planar

B.

octahedral

C.

square planar

D.

tetrahedral

Correct answer is A

Ammonia = NH3

It has three bonds of hydrogen to the Nitrogen.

6,544.

\(^{226}_{88}Ra\) → \(^x_{86}Rn\) + alpha particle

A.

226

B.

220

C.

227

D.

222

Correct answer is D

\(^{226}_{88}Ra\) → \(^x_{86}Rn\) + \(^4_{2}He\)

\(^4_{2}He\) = alpha particle

considering the summation of the mass number

226 = x + 4

x = 226 - 4

x = 222

6,545.

The ideal gas laws and equations are true for all gases at

A.

low pressures and lower temperatures

B.

low temperatures and high pressures

C.

high pressures and high temperatures

D.

low pressure and high temperatures

Correct answer is D

At high temperature and low pressure, the vanderwaal equation is reduced to ideal gas equation.

i.e, [P + \(\frac{a}{v^2}\)] [v - b] = RT is reduced to PV = nRT

Generally, a gas behaves more like an ideal gas at higher temperature and lower pressure as the potential energy due to intermolecular forces, it becomes less significant compared with the particles kinetic energy and the size of the molecules, then it becomes less significant compared to the empty space between them.