SOLUTIONS AND CONCENTRATIONS
A solution is a type of mixture in which one substance dissolves in another. In a
solution, the substance that is dissolved is called the solute. The substance that does
the dissolving is called the solvent. Water is the most common solvent. Most solutions
cannot be separated by simple physical means (for example, filtering). In a solution, any
part of the solution will have the same number of solute particles.
PREPARING AND USING SOLUTIONS
To prepare a solution of a given percentage, dissolve the given number of grams of
milliliters of solute in the given amount of solvent. When we specify the amounts of each
part of the solution, we have specified the concentration of the solution. Concentration is
the ratio or percentage amount of solute in a solvent.
Answer the following questions:
You place 1 mL of salt in a beaker, add 99 mL of water and stir thoroughly.
1. What percent of the total mixture is salt?
______________
2. What percent of the total mixture is water?
______________
You place 1 ml of sugar in a beaker, add 49 mL of water and stir thoroughly.
3. What percent of the total mixture is sugar?
_____________
4. What percent of the total mixture is water?
_____________
In order to find the percentage concentration, you must find out the total volume of the
solution, and divide the amount of solute by the total volume of solution.
5. What is the concentration of salt in the solution? _____ Water____?
6. What is the concentration of sugar in the solution? _____ Water____?
7. What would the concentration of each substance be in the following mixture?
Mix 280 mL water, 15 mL salt, 5 mL sugar. SHOW YOUR WORK!
Water concentration______ Salt concentration______
Sugar concentration______
8. In the above solution how would the concentration of salt at the bottom of the
beaker compare to the concentration of salt at the top of the beaker?
9. If you mixed sand and water together in a beaker, what would eventually
happen to the mixture if it was left undisturbed for a while? Is this a solution?
10. You make a 5% solution of salt water. You pour 50 mL in a 250 mL beaker.
You put one dropperful in a test tube. You put 3 drops of the solution in a
graduated cylinder.
What is the concentration of the salt solution in the beaker? ________
What is the concentration of the salt solution in the test tube? _______
What is the concentration of the salt solution in the cylinder? _______
Does the volume of the solution affect the concentration? _______
11. What is the concentration of each substance in the following solution?
5 mL of solution composed of 4.2 mL water, 0.5 mL sugar and 0.3 mL of salt.
SHOW YOUR WORK. Show concentrations as a percentage.
Water_________
Sugar__________
Salt_________
12. Each liter of Mountain Dew had dissolved 36 grams of sugar and 5 grams of
caffeine. The total mass of the liter is 1000 g.
What is the concentration of sugar in the Mountain Dew? _________
What is the concentration of caffeine in the Mountain Dew? ________
13. If 1% of the drink is made up of artificial flavors and preservatives and the
rest is water, then what is the concentration of water in Mountain Dew?
14. Show how you would make 100 mL of a 23% glucose solution.
15. Show how you would make 1500 mL of a 3% salt solution.
16. Each liter (1000 mL) of air in our atmosphere contains 780 mL of nitrogen
gas, 200 mL of oxygen gas, 0.3 mL of carbon dioxide gas and the remaining
19.7 mL of the air is a mixture of water vapor and other gases.
What is the concentration of oxygen in the air? ____________
What is the concentration of nitrogen in the air? _____________
What is the concentration of carbon dioxide in the air? ____________
What is the concentration of water vapor and trace gases in the
air?__________