JAMB Chemistry Past Questions & Answers - Page 218

1,086.

One mole of propane is mixed with five moles of oxygen. The mixture is ignited and the propane burns completely. What is the volume of the products at s.t.p?

(G.M.V = 22.4 dm³ mol^-1)

112.0 dm³

67.2 dm³

56.0 dm³

44.8 dm³

View answer & explanation

Correct answer is B

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
When the mixture is ignited CO₂ is collected as product. From the equation 33 moles of CO₂ is produced which equals 3 x 2.4 dm³ = 67.2 dm³ at S.T.P

1,087.

2.25g of a sample of an oxide of copper on reduction gave 2.0g of copper. 2.50g of another oxide of copper on reduction also gave 2.0g of copper. These results are in accordance with the law of?

constant composition

conservation of matter

multiple proportions

definite proportions

View answer & explanation

Correct answer is C

law of multiple proportions, statement that when two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.

1,088.

The formula of a compound formed in a reaction between a trivalent metal M and a tetravalent non-metal X is~?

M₃X₄

M₄X₃

M₃X₂

View answer & explanation

Correct answer is C

M²⁺ + X^-4 = M₄X₃