Question

When Z grams of calcium carbonate completely burnt in air gives 28g of a solid compound, the mass of calcium carbonate used will be:

• A. 200g
• B. 100g
• C. 56g
• D. 50g

Hint:

The mass of a compound produced in a chemical reaction can be calculated using the stoichiometric ratio between reactants and products.

Answer 1

The Correct Option is D

The reaction for the burning of calcium carbonate is: \[ \text{CaCO}_3 \xrightarrow{\text{heat}} \text{CaO} + \text{CO}_2 \] From the reaction, we know the molar mass of calcium carbonate (CaCO\(_3\)) is 100 g/mol, and calcium oxide (CaO) is 56 g/mol.
The stoichiometric ratio is 1:1, meaning that 100 g of calcium carbonate gives 56 g of calcium oxide.
Therefore, if 28 g of calcium oxide is produced, the mass of calcium carbonate required is: \[ \frac{100}{56} \times 28 = 50 \, \text{g} \]
Thus, the correct answer is (d).