Concentration Practice Problems

Question 1

Danika mixed 70g of lemonade in 900ml of water since she liked very plain lemonade for her sensitive taste buds. This means the drinks concentration should be 0.77g/ml. True or False?

Answer 1

False.

70g/900ml=7.7g/100ml

Question 2

Hunter dissolves 76 ml of Hot Chocolate mix into 150 ml of cold water. What is the concentration percentage?

Answer 2

76ml/150ml=0.506 x100 = 51%

Question 3

Elena wants to set up a lemonade stand to make some money. She discovers that the customers like a 25% concentrated solution the best. If she makes 1L of juice, how many ml of solute should she add?

Answer 3

1L=(1000ml) x 0.25 = 250ml of solute

Question 4

If Bella the good witch needs her potion of unicorn tears to be 37% tears and 63% river water. How much of each must she add to a 250ml solution?

Answer 4

250ml x 0.63= 157.5ml

250ml x 0.37= 92.5ml

Bella will need 157.5ml of river water, and 92.5ml of unicorn tears.