A solution is made up of 20 mL of water, 35 mL of isopropyl alcohol, and 8 mg of an organic solid. Which of these considered a solute?

Question

1. Water

 

2. Isopropyl alcohol

 

3. Medication

 

4. Water and isopropyl alcohol 

 

5. There is no solute in this solution 

 

We think it's medication. We also know that there can only be only 1 solvent and many solutes. Thanks

 

 

Answer 1

Hello Kacy

 

By definition, in a solution, the solvent is the substance that is present in the largest amount and the solute(s) is/are the substance(s) that is/are present in a smaller amount(s).

 

In your question, the volumes of water and isopropyl alcohol are given in units of mL, but the organic solid is listed in units of mg.  A better comparison would be to convert the volumes of water and isopropyl alcohol to units of mass using their densities (which you can google).   Density of water = 1.0 g/mL and density of isopropyl alcohol = 0.79 g/mL

 

Water:  20 mL x 1.0 g/mL = 20 g (x 1000 mg / 1 g = 20,000 mg)

 

Isopropyl alcohol: 35 mL x 0.79 g/mL = 28 g (x 1000 mg / 1 g = 28,000 mg)

 

Mass of organic solid (presumably the medication from the answer choices) = 8 mg

 

From the above, you can see that isopropyl alcohol is the substance that is present in the largest quantity, therefore, it is the solvent.  This would then make water and the medication the solutes.

 

However, if you had to select only ONE answer from the choices given, then the solute would be the medication (8 mg), because realistically, you can prepare a solution using a mixture of 2 solvents.

Answer 2

I think water is the solvent, so isopropyl alcohol and the organic solid would be the solutes.