Jamb Chemistry Past Questions For Year 1998

Question 1

90.0g of MgCI₂ was placed in 50.0cm³ of water to give a saturated solubility of the salt is 8.0 mol dm³ at the same temperature, what is the mass of the salt left undissolved at the given temperature?

(Mg = 24, Cl = 35.5)

jamb 1998

• A. 52.0g
• B. 58.5g
• C. 85.5g
• D. 88.5g

Question 2

If an element X of an atomic number Z and mass number Y is irradiated by an intense concentration of neutrons, the relevant nuclear equation is?

jamb 1998

• A. ^y_zX + ¹₀n → ^{y - 1}_{z + 1}X
• B. ^y_zX + ¹₀n → ^{y + 1}_zX
• C. ^y_zX + ¹₀n → ^y_{z + 1}X
• D. ^y_zX + ¹₀n → ^{y + 1}_{z - 1}X

Question 3

Excess phosphorus was burnt in a gas jar and the residual gas passed successively over concentrated KOH solution and concentration H₂SO₄ before being collected in a flask. The gases collected are?

jamb 1998

• A. carbon (IV) oxide, nitrogen and the rare gases
• B. nitrogen and the rare gases
• C. carbon (IV) oxide, nitrogen (IV) oxide and the rare gases
• D. carbon (IV) oxide

Question 4

The soil around a battery manufacturing factory is likely to contain a high concentration of?

jamb 1998

• A. Ca²⁺ salts
• B. Pb²⁺ salts
• C. Mg²⁺ salts
• D. Al³⁺ salts

Question 5

A gas that turns a filter paper previously soaked in lead ethanoate solution black is?

jamb 1998

• A. hyrogen chloride
• B. hydrogen sulphide
• C. sulphur (IV) oxide
• D. sulphur (VI) oxide