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UTME Chemistry 1999 JAMB Past Questions and Answers, Jamb, Pre-degree, Nursing, Waec, Neco

UTME Chemistry 1999 JAMB Past Questions and Answers, Jamb, Pre-degree, Nursing, Waec, Neco

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UTME Chemistry 1999 JAMB Past Questions and Answers

1. A pair of compounds that can be used to generate a gas which has physiological effect on human beings is

Options

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A) sodium trioxonitrate (V) and calcium chloride

B) sodium dioxonitrate (III) and ammonium chloride

C) sodium trioxonitrate (V) and ammonium chloride

D) sodium dioxonitrate (III) and potassium chloride

The correct answer is A.

2. Hydrogen is used in oxy-hydrogen flames for melting metals because it

Options

A) evolves a lot of heat when burnt

B) combines explosively with oxygen

C) is a very light gas

D) is a rocket fuel

The correct answer is A.

3. What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?

[ F = 96 5000 C mol-1 ]

Options

A) 24 125 coulombs

B) 48 250 coulombs

C) 72 375 coulombs

D) 96 500 coulombs

The correct answer is B.

Explanation:

4 Faradays of electricity is required to liberate one mole of oxygen gas

∴ quantity of electricity required

= 0.125 * 4 * 96500 = 48250 coulombs

4. X + Y → Z. The rate equation for the chemical reaction above is ((-Δ[x])/Δt) = K[X]2[Y].

The overall order of the reaction is

Options

A) 0.0

B) 1.0

C) 2.0

D) 3.09

The correct answer is D.

5. When a current I was passed through an electrolyte solution for 40 minutes, a mass X g of a univalent metal was deposited at the cathode. What mass of the metal will be deposited when a current 2I is passed through the solution for 10 minutes?

Options

A) X/4 g

B) X/2 g

C) 2X g

D) 4X g

The correct answer is B.

Explanation:

From M = zit

Where M = to the mass of the metal liberated

z = Is the electrochemical equivalent

∴ X g = 1 * 1 * 40 * 60

X g = 2400 I

Let Y represent the new mass

Y = 1*2I * 10 * 60

Y = 1200 I

Y/(X g) = 1200 I/2400 I

Y = X/2 g

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