SS2 (Chemistry Exam)

What is the amount (in mole) of sodium trioxocarbonate (IV) in 5.3g of the compound? [Na₂CO₃ = 106]

• 0.05

• 0.10

• 0.20

• 0.50

The volume of 2.5 moles of oxygen gas at S.T.P

[ one mole of a gas at S.T.P =22.4dm³]

• 50.0dm³

• 84.0dm³

• 28.0dm³

• 56.0dm³

What is the molar mass of a substance, if 0.4 mole of the substance has a mass of 25.0g?

• 62.5g/mol

• 40.0g/mol

• 6.3g/mol

• 2.5g/mol

The number of particles in one mole of a chemical compound is the

• atomic number

• Avogadro’s number

• mass number

• oxidation number

What is the amount of magnesium that would contain 1.20 x 10²³ particles [Mg = 24, Avogadro’s constant = 6.02 x 10²³]

• 0.5 mole

• 0.2 mole

• 12.0 moles

• 24.0 moles

How many moles of oxygen would contain 1.204 x 10²⁴ molecules? [Avogadro’s constant (N_A) = 6.02 x 10²³]

• 1

• 2

• 3

• 4

How many molecules are there in 14g of nitrogen gas, N₂ at s.t.p?

[N = 14, Avogadro Number = 6.0 x 10²³]

• A.1.2 x 10²³

• B. 3.0 x 10²³

• C. 6.0 x 10²³

• D. 1.2 x 10²⁴

1.What is the mass of 6.02 x 10²⁴ atoms of magnesium?[Mg=24, Avogadros constant =6.02 x 10²³ mol^-1] [WAEC]

• 24

• 240

• 2.4

• 6.02

1.A chip used in microcomputer contains 5.74x 10^-3 g of silicon. Calculate the number of silicon atoms in the chip.(Si=28; Avogadro constant=6.02 x 10²³ )

• 1.23 x 10²⁰

• 1.23 x 10²³

• 5.74 x 10²⁴

• 1.00 x 10²¹

How many mole of AgNO₃ are there in 500cm³ of 0.01M AgNO₃ solution?

• 0.005

• 0.5

• 0.25

• 0.2