Suppose4.0g of sodium hydroxide were dissolved in 400cm3 of distilled water then made up to 500cm3 of solution. Determine the concentration in g and moles
To determine the concentration in g, divide the mass of sodium hydroxide by the volume of the solution:
concentration (g/cm3) = 4.0g / (500cm3) = 0.008g/cm3
To determine the concentration in moles, we need to use the molar mass of sodium hydroxide (NaOH), which is 22.99 g/mol for sodium (Na), 16.00 g/mol for oxygen (O), and 1.01 g/mol for hydrogen (H):
molar mass of NaOH = (22.99 g/mol) + (16.00 g/mol) + (1.01 g/mol)
= 39.00 g/mol
Now divide the mass of sodium hydroxide by the molar mass:
moles of NaOH = 4.0g / (39.00 g/mol) = 0.102 moles