Determine the number of moles of calcium carbonate with 10% impurities, which reacts with 21.9 g of hydrochloric acid.
To determine the number of moles of calcium carbonate, we need to follow these steps:
Step 1: Calculate the molar mass of calcium carbonate.
The formula for calcium carbonate is CaCO3.
The molar mass of Ca = 40.08 g/mol,
the molar mass of C = 12.01 g/mol,
and the molar mass of O = 16.00 g/mol (there are 3 oxygen atoms in the compound).
So, the molar mass of calcium carbonate (CaCO3) is:
(1 x 40.08 g/mol) + (1 x 12.01 g/mol) + (3 x 16.00 g/mol) = 100.09 g/mol.
Step 2: Calculate the mass of pure calcium carbonate.
Since the calcium carbonate contains 10% impurities, the remaining 90% will be the pure calcium carbonate.
So, the mass of pure calcium carbonate is 90% of the given mass. We can calculate it as follows:
90% × mass of calcium carbonate = 90/100 × mass of calcium carbonate = 0.9 × mass of calcium carbonate.
Step 3: Calculate the moles of pure calcium carbonate.
To calculate the moles, we can use the formula:
moles = mass / molar mass.
So, the number of moles of pure calcium carbonate is:
moles = (0.9 × mass of calcium carbonate) / molar mass of calcium carbonate.
Step 4: Substitute the given values and calculate.
Given: mass of hydrochloric acid = 21.9 g.
Using the balanced chemical equation, we know that 1 mole of CaCO3 reacts with 2 moles of HCl.
So, the moles of pure calcium carbonate can be calculated as:
moles = (0.9 × mass of calcium carbonate) / molar mass of calcium carbonate = (0.9 × 21.9 g) / 100.09 g/mol.
By following these steps, you can calculate the number of moles of calcium carbonate that reacts with 21.9 g of hydrochloric acid.