Final answer:
To determine how much benzoic acid will crystallize after cooling to 20°C, subtract the mass of salicylic acid from the total mass of the sample.
Step-by-step explanation:
To determine how much benzoic acid will crystallize after cooling to 20°C, we need to consider the solubility of benzoic acid and salicylic acid at that temperature. Benzoic acid has a lower solubility than salicylic acid at 20°C, so it will be the compound to crystallize out.
To calculate the mass of benzoic acid that will crystallize, we need to subtract the mass of the salicylic acid from the total mass of the sample. In this case, we subtract 0.05 g from 1.0 g to get 0.95 g of benzoic acid that will crystallize.