Question

Calculate the mass/volume percent, % (m/v), for the solute in each of the following solutions.

a) 2.00 g KCl in 60.0 mL of solution

b) 8.0 g of casein in 150 mL of low-fat milk

Answer 1

Answer 2

Calculations:

a) 2.00 g KCl in 60.0 mL solution

1. Formula:

   $$\mathrm{\%}(m\mathrm{/}v)=\left(\frac{\text{mass of solute (g)}}{\text{volume of solution (mL)}}\right)\times 100$$

2. Plug in the numbers:

   $$\mathrm{\%}(m\mathrm{/}v)=\left(\frac{2.00\text{ g}}{60.0\text{ mL}}\right)\times 100=3.33\mathrm{\%}$$

3. Translation:
   "This solution has 3.33 grams of KCl per 100 mL—like a pinch of salt in a small cup of water."

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b) 8.0 g casein in 150 mL low-fat milk

1. Same formula:

   $$\mathrm{\%}(m\mathrm{/}v)=\left(\frac{8.0\text{ g}}{150\text{ mL}}\right)\times 100=5.33\mathrm{\%}$$

 

Answer:

Mass/Volume Percent (% m/v) Explained Simply

This tells you how many grams of solute are dissolved in every 100 mL of solution. Think of it like a "grams per 100 mL" recipe!