# The mixture contains calcium carbonate and magnesium carbonate. Calculate the mass fraction

The mixture contains calcium carbonate and magnesium carbonate. Calculate the mass fraction of calcium carbonate if the amount of the substance is 0.3 mol, and the amount of magnesium carbonate is 0.25 mol?

Given:
n (CaCO3) = 0.3 mol
n (MgCO3) = 0.25 mol

Find:
ω (CaCO3) -?

Solution:
1) M (CaCO3) = Mr (CaCO3) = Ar (Ca) * N (Ca) + Ar (C) * N (C) + Ar (O) * N (O) = 40 * 1 + 12 * 1 + 16 * 3 = 100 g / mol;
2) m (CaCO3) = n (CaCO3) * M (CaCO3) = 0.3 * 100 = 30 g;
3) M (MgCO3) = Mr (MgCO3) = Ar (Mg) * N (Mg) + Ar (C) * N (C) + Ar (O) * N (O) = 24 * 1 + 12 * 1 + 16 * 3 = 84 g / mol;
4) m (MgCO3) = n (MgCO3) * M (MgCO3) = 0.25 * 84 = 21 g;
5) m mixture = m (CaCO3) + m (MgCO3) = 30 + 21 = 51 g;
6) ω (CaCO3) = m (CaCO3) * 100% / m mixture = 30 * 100% / 51 = 58.82%.

Answer: The mass fraction of CaCO3 is 58.82%. One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.