# Calculate the molecular weight Mr – CO2, mn2o7, H3PO4, NaNo3, N2O3, СaSo4, Fe2O3, H2SiO3

To calculate the molecular weight of a substance, it is necessary to sum up the relative atomic masses (Ar) of all elements, taking into account the amount of substance (n).
Mr (CO2) = Ar (C) + 2Ar (O) = 12 + 2 • 16 = 44 g / mol.
Mr (Mn2O7) = 2Ar (Mn) + 7Ar (O) = 2 • 55 + 7 • 16 = 222 g / mol.
Mr (H3PO4) = 3Ar (H) + Ar (P) + 4Ar (O) = 3 • 1 + 31 + 4 • 16 = 98 g / mol.
Mr (NaNO3) = Ar (Na) + Ar (N) + 3Ar (O) = 23 + 14 + 3 • 16 = 85 g / mol.
Mr (N2O3) = 2Ar (N) + 3Ar (O) = 2 • 14 + 3 • 16 = 76 g / mol.
Mr (CaSO4) = Ar (Ca) + Ar (S) + 4Ar (O) = 40 + 32 + 4 * 16 = 136 g / mol.
Mr (Fe2O3) = 2Ar (Fe) + 3Ar (O) = 2 • 56 + 3 • 16 = 160 g / mol.
Mr (H2SiO3) = 2Ar (H) + Ar (Si) + 3Ar (O) = 2 • 1 + 28 + 3 • 16 = 78 g / mol. 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.