REFERENCE SECTION: INTRODUCTION - CHEMICAL CALCULATIONS (2) Molar Mass (M) The molar mass (M) of a substance has the same numerical value as its relative atomic or molecular mass, but has the units g mol-¹.
Masses into Moles The conversion of masses into moles requires the use of this equation: Number of moles (n) of substance = Mass (m) ÷ Molar mass (M)
Moles into Masses The conversion of moles into masses requires the use of this equation: Mass (m) of substance = Number of moles (n) × Molar mass (M)
Concentration of a Solution The concentration (C) of a solution, expressed as mol dm-³, is the number of moles (n) of solute dissolved in a volume (V) of one cubic decimetre of solvent; this quantity is calculated using this equation: Conc. (C) of soln. = No. of moles (n) of solute ÷ Vol. (V) of solvent
Density of a Gas The density (D) of a gas, expressed in g cm-³, is the mass (m) of gas contained in a volume (V) of one cubic centimetre. Because experiments have shown that 1 mole of any gas, at room temperature and pressure (r.t.p.), occupies a volume of 24000 cm³, the density of a gas can be calculated using this equation: Density (D) of a gas = Molar mass (M) ÷ 24000
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