Question

Обчисліть відносну молекулярну масу: Mr(NaOH) Mr(Ca(OH)2) Mr(AL(OH)3)

Answer 1

Mr(NaOH) = 23 + 16+1 = 40
Mr(Ca(OH)2) = 40+(16+1)*2 = 74
Mr(AL(OH)3)= 27 + (16+1)*3 = 78

Answer 2

Mr(NaOH) = 23.0 (molar mass of Na) + 16.0 (molar mass of O) + 1.0 (molar mass of H) = 40.0 g/mol

Mr(Ca(OH)2) = 40.1 (molar mass of Ca) + 2(16.0) (molar mass of O) + 2(1.0) (molar mass of H) = 74.1 g/mol

Mr(AL(OH)3) = 27.0 (molar mass of Al) + 3(16.0) (molar mass of O) + 3(1.0) (molar mass of H) = 78.0 g/mol

Therefore, the relative molecular masses are:

Mr(NaOH) = 40.0 g/mol Mr(Ca(OH)2) = 74.1 g/mol Mr(AL(OH)3) = 78.0 g/mol

Note: Relative molecular mass is also called molar mass.