Question

mylanta is a common over the counter antiacid medicine. The active ingresdients in one 5.0 ml dose re 500 mg of aluminium hydroxide al(oH)2 and 500 mg of magnisium hydroxide mg(oH)2 what is the total molar concentration of hydroxide ions oH in mylanta

Answer 1

Mass of Al(OH)3 = 500 mg = 0.50 g

Molar mass of Al(OH)3 = 78.0036 g/mol

Moles of Al(OH)3 = 0.50 g / 78.0036 g/mol

= 0.00640 moles

Moles of OH- ions = 3 * 0.00640 moles

= 0.0192 moles

Mass of Mg(OH)2 = 500 mg = 0.50 g

Molar mass of Mg(OH)2 = 58.3197 g/mol

Moles of Mg(OH)2 = 0.50 g / 58.3197 g/mol.

= 0.00857 moles

Moles of OH- ions = 2 * 0.00857 moles

= 0.01714 moles

Total moles of OH- ions = 0.0192 moles + 0.01714 moles

= 0.03634 moles

Volume of dose = 5.0 mL = 0.005 L

[OH-] in mylanta = 0.03634 moles / 0.005 L

= 7.26 M