Question 441:

• JAMB 1985

Given that the molecular mass of iron is 56 and that of oxygen is 16, how many moles of iron(iii)oxide will be contained in 1kg of the compound?

A. 25.0 moles
B. 12.5 moless
C. 6.25 moles
D. 3.125 moles
E. 0.625 moles

Question 442:

• JAMB 1985

3.0g of a mixture of potassium carbonate and potassium chloride were dissolved in a 25cm³ of this solution required required 40.00cm₃ of 0.1M HCl for neutralization. What is the percentage by weight of K₂CO₃ in the mixture. (K = 39, O = 16, C = 12)

A. 60
B. 72
C. 82
D. 89
E. 92

Question 443:

• JAMB 1985

Some properties of chemical substances are mentioned below... i. sour taste ii. slippery touch iii. yields alkaline gas with ammonium salt iv. has pH less than 7 v. turns phenolphthalein pink.
Which of the above are NOT typical properties of alkalis?

A. I, iv and v
B. Iv and v
C. I and iv
D. Ii and v
E. Ii, iii and iv

Question 444:

• JAMB 1985

A certain volume of gas at 298k is heated such that its volume and pressure are now four times the original values. What is the new temperature?

A. 18.6k
B. 100.0k
C. 298.0k
D. 1192.0k
E. 4768.0k

Question 445:

• JAMB 1985

Hydrogen is not liberated when trioxonitrate(v)acid reacts with zinc because

A. Zinx is not rendered passive by acid
B. Hydrogen produced is oxidized to water
C. Oxides of nitrogen are produced
D. All nitrates are soluble in water
E. Trioxonitrate(v)acid is a strong acid