40 g of calcium was extracted from 56 g of calcium oxide

(Atomic mass of Ca= 40, O=16)

i) What mass of oxygen is there in 56 g of calcium oxide?

ii) How many moles of oxygen atoms are there in this?

iii) How many moles of calcium atoms are there in 40 g of calcium?

iv) What mass of calcium will be obtained from 1000 g of calcium oxide?

Nitro glycerine is used as an explosive. The equation for the explosive reaction is

4C₃H₅((NO₃))₃12CO₂ + 10H₂O + 6N₂ + O₂

(l) (g) (l) (g) (g)

(Atomic mass of C = 12, H = 1, N = 14, O=16)

1. How many moles does the equation show for i) Nitroglycerine ii) gas molecules produced?

2. How many moles of gas molecules are obtained from 1 mole of nitroglycerine?

3. What is the mass of 1 mole of nitroglycerine?

Sodium bi carbonate breaks down on heating:

2NaHCO₃ Na₂CO₃ + H₂O + CO₂

(Atomic mass of Na = 23, C = 12, H = 1, O=16)

i) How many moles of sodium bi carbonate are there in the equation?

ii) What is the mass of sodium bicarbonate used in this equation?

iii) How many moles of carbon dioxide are there in this equation?

How many grams are there in the following?

i) 1 mole of chlorine molecule, Cl₂

ii) 2 moles of sulphur molecules, S₈

iii) 4 moles of ozone molecules, O₃

iv) 2 moles of nitrogen molecules, N₂

Find how many moles of atoms are there in:

i) 2 g of nitrogen.

ii) 23 g of sodium

iii) 40 g of calcium.

iv) 1.4 g of lithium

v) 32 g of sulphur.