You need to prepare a 5% (w/v) milk solution to use in your experiment.

Question

You need to prepare a 5% (w/v) milk solution to use in your experiment. In the lab, we have dry powdered milk that you can dissolve in your solvent (water). Describe how you would make 400 mL of a 5% milk solution.

Dissolve 100 g milk powder into water to attain a final volume of 400 mL

Dissolve 0.4 g milk powder into water to attain a final volume of 400 mL

Dissolve 40 g milk powder into water to attain a final volume of 400 mL

Dissolve 20 g milk powder into water to attain a final volume of 400 mL

Thank you.

Answer 1

Hi Jas A.!

The preparation of a percent w/v solution is prepared by use of the following formula:

% w/v = (g of solute/100mL of solution) x 100%

To prepare a 400 mL milk solution that is 5% w/v, simply rearrange the equation:

% w/v = (g of solute/400mL of solution) x 100% => mass of solute = (% w/v/100%) x 400mL

<=> (5%/100%) x 400

mass of solute = 20g milk

Hope this helps!

Cheers