A sample of MgCO3 has a mass of 17.695 g. How many moles does the sample contain?
To determine the number of moles in a sample, you need to use the formula:
moles = mass / molar mass
First, we need to find the molar mass of MgCO3 (magnesium carbonate).
The molar mass can be calculated by adding up the atomic masses of each individual atom in the compound.
The atomic masses for magnesium (Mg), carbon (C), and oxygen (O) are 24.305 g/mol, 12.011 g/mol, and 16.00 g/mol, respectively.
Molar mass of MgCO3 = (1 * molar mass of Mg) + (1 * molar mass of C) + (3 * molar mass of O)
Molar mass of MgCO3 = (1 * 24.305 g/mol) + (1 * 12.011 g/mol) + (3 * 16.00 g/mol)
Molar mass of MgCO3 = 24.305 g/mol + 12.011 g/mol + 48.00 g/mol
Molar mass of MgCO3 = 84.316 g/mol
Now, we can calculate the moles using the formula:
moles = mass / molar mass
moles = 17.695 g / 84.316 g/mol
moles ≈ 0.2099 mol
Therefore, the sample of MgCO3 contains approximately 0.2099 moles.