H2SO4 Molar Mass
Molar mass is an essential concept in chemistry that refers to the mass of one mole of a substance. It is a crucial parameter for various calculations, including the determination of the amount of reactant required in a chemical reaction, the determination of empirical and molecular formulas, and the conversion of mass to moles and vice versa. In this article, we will discuss the molar mass of H2SO4 in detail, including its definition, calculation, and significance in various chemical applications.
Definition of H2SO4 Molar Mass
The molar mass of sulfuric acid is defined as the mass of one mole of sulfuric acid molecules. It is expressed in grams per mole (g/mol) and is calculated by adding up the atomic masses of all the atoms in the molecule. The chemical formula of sulfuric acid is H2SO4, which means it contains two hydrogen atoms (H), one sulfur atom (S), and four oxygen atoms (O).
Calculation of H2SO4 Molar Mass
To calculate the molar mass of sulfuric acid, we need to determine the atomic masses of all the atoms present in the molecule and add them up. The atomic mass of hydrogen is 1.008 u, sulfur is 32.06 u, and oxygen is 15.999 u. Therefore, the molar mass of sulfuric acid can be calculated as follows:
Molar mass of H2SO4 = (2 × atomic mass of H) + atomic mass of S + (4 × atomic mass of O) = (2 × 1.008 u) + 32.06 u + (4 × 15.999 u) = 98.08 g/mol
Therefore, the molar mass of H2SO4 is 98.08 g/mol.
Significance of Sulfuric Acid Molar Mass
The molar mass of sulfuric acid is significant in various chemical applications. It is used to determine the amount of reactant required in a chemical reaction. For example, if we want to react 10 g of H2SO4 with magnesium, we need to know the number of moles of sulfuric acid present in 10 g. This can be calculated using the molar mass of sulfuric acid as follows:
Number of moles of H2SO4 = Mass of H2SO4 / Molar mass of H2SO4 = 10 g / 98.08 g/mol = 0.102 moles
Therefore, 10 g of sulfuric acid contains 0.102 moles of sulfuric acid.
Empirical and molecular formulas:
The molar mass of sulfuric acid is also used to determine the empirical and molecular formulas of compounds. The empirical formula is the simplest whole-number ratio of atoms in a compound, while the molecular formula represents the actual number of atoms of each element in a molecule. The molar mass of a compound is used to determine the molecular formula from the empirical formula. For example, if the empirical formula of a compound is CH2O and its molar mass is 180 g/mol, its molecular formula can be calculated as follows:
Empirical formula mass = (1 × atomic mass of C) + (2 × atomic mass of H) + (1 × atomic mass of O) = 12.011 g/mol + (2 × 1.008 g/mol) + 15.999 g/mol = 30.026 g/mol
Number of empirical formula units in 180 g/mol = 180 g/mol / 30.026 g/mol = 5.995
Therefore, the molecular formula of the compound is (CH2O)5.995, which is approximately equal to C5H10O5.
Molarity:
Furthermore, the molar mass of sulfuric acid is also essential in determining the concentration of solutions in terms of molarity. Molarity is defined as the number of moles of solute dissolved in one liter of solution. The molar mass of sulfuric acid is used to calculate the number of moles of H2SO4 present in a given volume of solution. For example, if we dissolve 10 g of sulfuric acid in 500 mL of water, we can calculate the molarity of the solution as follows:
Number of moles of H2SO4 = Mass of H2SO4 / Molar mass of H2SO4 = 10 g / 98.08 g/mol = 0.102 moles
Volume of solution in liters = 500 mL / 1000 mL/L = 0.5 L
Molarity of the solution = Number of moles of H2SO4 / Volume of solution in liters = 0.102 moles / 0.5 L = 0.204 M
Therefore, the molarity of the solution is 0.204 M.