An impure sample contains 0.95g of benzoic acid and 0.05 of salicylic acid. Solubilities in water of the two compounds are given in the following table.

Solubility at 20 degrees (g/10mL)
benzoic acid: 0.029
salicylic acid: 0.22

Solubility at 100 degrees (g/10mL)
benzoic acid: 0.680
salicylic acid: 6.67

--> What is the minimum volume of boiling water needed to dissolve the 1.0 g sample?

I'm not sure on what to do. Do I use the solubilities at boiling point for each to find the volumes and then just add the volumes together?

Benzoic acid is much less soluble than salicylic acid; therefore, add enough water at the 100 C to dissolve the benzoic acid and the S. A. will take care of itself.

So for the actual calculation.. would i just go 0.95 g benzoic acid * (10mL/0.680 g)?

That's correct.

To find the minimum volume of boiling water needed to dissolve the 1.0 g sample, you need to consider the solubilities of benzoic acid and salicylic acid at the boiling point of water.

Here's the step-by-step process:

1. Calculate the mass of benzoic acid and salicylic acid in the 1.0 g sample.
- Mass of benzoic acid = 0.95 g
- Mass of salicylic acid = 0.05 g

2. Determine the required volumes of water to dissolve the benzoic acid and salicylic acid separately at their solubility limits.
- For benzoic acid, use the solubility at the boiling point: 0.680 g/10mL
- Volume of water to dissolve benzoic acid = mass of benzoic acid / solubility at boiling point
V_benzoic_acid = 0.95 g / 0.680 g/10mL

- For salicylic acid, use the solubility at the boiling point: 6.67 g/10mL
- Volume of water to dissolve salicylic acid = mass of salicylic acid / solubility at boiling point
V_salicylic_acid = 0.05 g / 6.67 g/10mL

3. Add the volumes of water required to dissolve benzoic acid and salicylic acid to find the minimum volume of boiling water needed to dissolve the sample.
Minimum volume of boiling water = V_benzoic_acid + V_salicylic_acid

4. Calculate the final result and round it to an appropriate precision.

Following these steps, you should be able to find the minimum volume of boiling water needed to dissolve the 1.0 g sample.