Question

Please show all work.

Given:

Mass of sodium acetate in acetate buffer - .6708 g

Volume of 6 M acetic acid in acetate buffer - 2.05 mL

Mass of potassium hydrogen phthalate (KHP) in the hydrogen phthalate buffer - 2.0633 g

Moles of sodium acetate in acetate buffer?

Molarity of sodium acetate in 250.0 mL acetate buffer?

Moles of acetic acid in 250.0 mL acetate buffer?

Molarity of acetic acid in acetate buffer?

Moles of KHP in hydrogen phthalate buffer?

Molarity of KHP in 250.0 mL hydrogen phthalate buffer?

Answer 1

Mass of sodium acetate in acetate buffer - 0.6708 g

Volume of 6 M acetic acid in acetate buffer - 2.05 mL

Molar mass of CH3COONa = 82.03 g/mol

That is

82.03 g of CH3COONa = 1 mole

0.6708g of CH3COONa = (0.6708 / 82.03) mole = 0.008 moles

Molarity = moles/Liter

So, molarity of 0.008 moles of CH3COONa in 250.0 mL = 0.008 moles / 0.25 L = 0.032 M

2.05 mL of 6 M acetic acid

So, moles of acetic acid = Molarity x Liter = 6 M x 0.00205 L = 0.0123 mole

So, moles of acetic acid in 250.0 mL acetate buffer = 0.0123 mole

Molarity of acetic acid in acetate buffer of 250 mL = 0.0123 mole / 0.25 L = 0.0492 M

Mass of potassium hydrogen phthalate (KHP) in the hydrogen phthalate buffer - 2.0633 g

Molar mass of potassium hydrogen phthalate = 204.22 g/mol

204.22 g of potassium hydrogen phthalate = 1 mole

2.0633 g of potassium hydrogen phthalate = (2.0633/204.22) mole = 0.01 moles

Molarity of potassium hydrogen phthalate in 250 mL = 0.01 moles/ 0.25 L = 0.04 M