Unit 3 Mole

How many lithium atoms that have the same mass as 2 nitrogen atoms?

[Relative atomic mass: Li = 7; N = 14]

• 2

• 4

• 6

• 8

2. What is the relative molecular mass of sulphur hexafluoride?

[Relative atomic mass: F = 19; S = 32]

• 51

• 108

• 133

• 146

The relative atomic mass of lead is 207. Which of the following statements is true?

[Relative atomic mass: Na = 23]

• 0.01 mol of lead has a mass of 2.07 g

• 20.7 g of lead contains 6.02 x 10²¹ atom

• 1 mol of lead has a volume of 24 dm³ at room temperature

• The mass of 1 lead atom is equal to the mass of 7 sodium atom

Which of the following substances has 3.01 x 10²³ of atom?

• 0.25 mole of water

• 0.5 mole of carbon

• 0.5 mole of oxygen gas

• 0.3 mole of hydrogen gas

What is the volume of a sample of ammonia gas, NH₃ with a mass of 5.1 g at room condition?

[Gas molar volume = 24 dm³ in room condition]

• 7.2 dm³

• 12 dm³

• 14.4 dm³

• 18 dm³

Which of the following is the correct chemical formula for copper(II) iodide?

• CuI

• Cu₂I

• CuI₂

• Cu₂I₂

1.2 g of element Y bonds with bromine to produce 6 g of a compound with the empirical formula of YBr₂. What is the relative atomic mass of element Y?

[Relative atomic mass: Br = 80]

• 20

• 36

• 40

• 56

Tags

NGSS.HS-PS1-7

The following is a chemical equation:

H₂SO₄(aq) + 2KOH(aq) → K₂SO₄(aq) + xH2O(l)

What is the value of x?

• 1

• 2

• 3

• 4

Tags

NGSS.HS-PS1-7

The complete combustion of ethanol is as follow:

C₂H₅OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(l)

What is the volume of oxygen gas that is needed at room condition to completely burn 9.2 g of ethanol?

[Relative atomic mass: H = 1, C = 12, O = 16; Molar volume = 24 dm³ mol^-1 at room condition]

• 4.8 dm³

• 9.6 dm³

• 14.4 dm³

• 19.2 dm³