To calculate the molar mass of magnesium nitrate [Mg NO3 2], we need to find the molar mass of each element in the compound and then add them together.1. Magnesium Mg : The molar mass of magnesium is 24.305 g/mol.2. Nitrogen N : The molar mass of nitrogen is 14.007 g/mol. Since there are two nitrogen atoms in each nitrate ion NO3- and two nitrate ions in the compound, there are a total of 4 nitrogen atoms. So, the total molar mass of nitrogen in the compound is 4 * 14.007 g/mol = 56.028 g/mol.3. Oxygen O : The molar mass of oxygen is 15.999 g/mol. There are three oxygen atoms in each nitrate ion NO3- and two nitrate ions in the compound, making a total of 6 oxygen atoms. So, the total molar mass of oxygen in the compound is 6 * 15.999 g/mol = 95.994 g/mol.Now, we add the molar masses of magnesium, nitrogen, and oxygen together:Molar mass of Mg NO3 2 = 24.305 g/mol Mg + 56.028 g/mol N + 95.994 g/mol O = 176.327 g/molSo, the molar mass of magnesium nitrate [Mg NO3 2] is 176.327 g/mol.