1. Which of the following has the greatest number of molecules?
A 0.1g of hydrogen gas
B 0.16g of methane
C 0.34g of ammonia
D 0.14g of nitrogen
2. How many moles of ions are present in 0.2 moles of alumnium sulphate
A 0.2 moles
B 0.4 moles
C 0.6 moles
D 1 mole
3. A mixture of magnesium bromide and magnesium sulfate is known to contain 3 mol of magnesium and 4 mol of bromide ions. How many moles of sulfate ions are present?
A 1
B 2
C 3
D 4
4. Find the number of atoms in ;-
a) 2 moles magnesium
b) 100g of calcium
5. Find the number of molecules in 4.6g of nitrogen dioxide.
6. The mass of 1 mol of sodium is 23 g. What is the approximate mass of one sodium atom?
A 6 × 1023g
B 6 × 10–23g
C 3.8 × 10–23g
D 3.8 × 10–24g
7. The Avogadro Constant is the same as the number of
A ions in 1 mol of NaCl
B atoms in 1 mol of hydrogen gas
C electrons in 1 mol of helium gas
D molecules in 1 mol of oxygen gas.
8. The Avogadro Constant is the same as
A the number of molecules in 16g Oxygen
B the number of ions in 1 litre of sodium chloride solution, concentration 1 mol-l
C the number of atoms in24g of carbon
D the number of molecules in 2g of Hydrogen
9. In which of the following pairs do the gases contain the same number of oxygen atoms?
A 1 mol of oxygen and 1 mol of carbon monoxide
B 1 mol of oxygen and 0.5 mol of carbon dioxide
C 0.5 mol of oxygen and 1 mol of carbon dioxide
D 1 mol of oxygen and 1 mol of carbon dioxide
10. The Avogadro Constant is the same as the number of
A molecules in 16 g of oxygen
B ions in 1 litre of sodium chloride solution, concentration 1 mol l–1
C atoms in 24 g of carbon
D molecules in 2 g of hydrogen.
