Day 1  Day 2  Day 3  Day 4  Day 5  Day 6

Day 1

Question 1

1.42 g of an oxide of phosphorus contains 0.62 g of phosphorus. Calculate its empirical formula.

Day 2

Question 1

Calculate the mass of calcium chloride​​ and volume of CO2​​ produced when 20 g of calcium carbonate reacts with excess hydrochloric acid.
*Reaction: CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂*

Day 3

Question 1

In an experiment, 5.0 g of calcium carbonate was heated. 2.8 g of calcium oxide was obtained.
Reaction: CaCO₃ → CaO + CO₂
a) Calculate the theoretical yield of calcium oxide.
b) Calculate the percentage yield.

Day 4

Question 1

A student neutralises 25 cm³ of 2.0 mol/dm³ sodium hydroxide with hydrochloric acid.
Reaction: NaOH + HCl → NaCl + H₂O
a) How many moles of NaOH were used?
b) What mass of sodium chloride is produced?

Day 5

Question 1

1.52 g of a dry metal carbonate was heated. It decomposed to give 0.88 g of metal oxide and carbon dioxide gas.
a) Write a general equation for the reaction: MCO₃ → MO + CO₂
b) Calculate the mass of CO₂ produced.
c) Calculate the number of moles of CO₂.
d) Calculate the Mᵣ​​ of the original metal carbonate and identify the metal M.

Day 6

Question 1

A 2.00 g sample of limestone (impure CaCO₃) is reacted with excess acid. 0.50 dm³ of CO₂ is produced.
a) Calculate the number of moles of CO₂ produced.
b) How many moles of pure CaCO₃ must have been present?
c) Calculate the mass of pure CaCO₃ that was present.
d) Calculate the percentage purity of the limestone sample.