Grade 12 Mixture Problems Worksheet

Grade 12 Mixture Problems

Read each problem carefully and solve for the unknown quantities. Show all your work. Use diagrams or tables to organize your information where helpful.

1. A chemist has two solutions of hydrochloric acid. One solution is 30% acid and the other is 70% acid. How much of each solution should be mixed to obtain 100 mL of a 50% acid solution?

2. An alloy containing 20% copper is mixed with an alloy containing 50% copper to form 150 kg of an alloy containing 30% copper. The amount of 20% copper alloy used is   kg, and the amount of 50% copper alloy used is   kg.

3. When mixing two solutions of different concentrations, the resulting concentration will always be between the two initial concentrations.

4. A candy store wants to mix two types of candy. One type sells for $5 per pound and the other sells for $8 per pound. How many pounds of the $5 candy should be mixed with 20 pounds of the $8 candy to get a mixture that sells for $6 per pound?

5. An investor has $20,000 to invest in two different funds. Fund A pays 4% interest annually, and Fund B pays 6% interest annually. If the investor wants to earn $1,000 in annual interest, how much should be invested in each fund?

6. Imagine you have a beaker of a 20% salt solution. If you add pure water to it, what happens to the concentration of salt? Draw a simple diagram to illustrate this process.