Waec Chemistry 2007 Past Questions and Answers

Question 11:

• WAEC 2007

Which of the following species does not contain a co-ordinate bond?

A. AI₂CI₆
B. CCI₄
C. H₃O⁺
D. NH ⁺₄

Question 12:

• WAEC 2007

14.8 g of a salt (z)dissolved in 250 cm³ of distilled water gives a concentration of 0.80 mol dm^-3. Calculate the molar mass of the salt (z).

A. 13.5 g mol^-1
B. 18.5 g mol^-1
C. 47.4 g mol^-1
D. 74.0 g mol^-1

Question 13:

• WAEC 2007

How many atoms are there in one mole of hydrogen gas? [Avogadro's constant = 6.02 x 10²³mol^-1]

A. 1.2 x 10 ²³
B. 6.0 x 10 ²³
C. 1.2 x10 ²⁴
D. 6.0 x 10 ²⁴

Question 14:

• WAEC 2007

What is the IUPAC name of the compound represented by the molecular formula NaCIO₄?

A. Sodium tetraoxochlorate (l)
B. Sodium tetraoxochlorate (IV)
C. Sodium tetraoxochlorate (VI)
D. Sodium tetraoxochlorate(VII)

Question 15:

• WAEC 2007

When air is successively passed through sodium hydroxide solution, alkaline pyrogallol and then concentrated tetraoxosulphate (VI) acid, its remaining components are

A. Oxygen and water vapour
B. Oxygen and nitrogen
C. Carbon (IV) acid and noble gases
D. Nitrogen and noble gases