Return to Chemistry IndexConcentration vs Solubility

Therese Donatello Archbishop Weber H. S.

5252 W. Palmer St.

Chicago IL 60639

(312) 637-7500

Objectives:

1. The student will be able to distinguish between concentration and solubility.

2. The student will be able to tell which solution is more concentrated.Materials Needed:

Bingo chips Petri dishes beans

bottles eye droppers food color

water table salt talcum powder

hot plate wax paper spoonsStrategy:

1. Ask the students to count the number of Bingo chips in each of the Petri

dishes. They will see that one has more chips than the other. Explain that

the one that has more chips is said to be more concentrated. Repeat using

dishes containing various amount of beans. Have the students rank the

containers from the highest to the lowest concentration.

2. Have the students fill a bottle half way with water. Add table salt (one

spoonful at a time while stirring) and have them describe what happens as

each spoonful is added until no more dissolves. Then have them do the same

thing using talcum powder. Explain that the table salt when it dissolves is

said to be soluble while the talcum powder which does not dissolve is said to

be insoluble. Ask the students to predict what will happen if you use hot

water instead of room temperature water. Then have them repeat the

demonstration using the hot water.

3. Have the students place one drop of food color on a piece of wax paper and

then add nine drops of water to the drop of food color. On a piece of paper

have the students draw ten circles and label the first one with the number

one. Ask the students to take one drop from #1 and place it on another spot

on the wax paper along with nine drops of water. Ask the students what part

of this solution is from the spot numbered one. Explain that one part is from

#1 so one out of ten drops is from #1. Have the students label the second

circle 1/10. Have them repeat this procedure for the remaining eight

circles.

Performance Assessment:

1. Students in the lower grades will be able to explain concentration by

counting the amount of a substance in a given amount of space. They will be

able to tell the difference between concentration and solubility by seeing if

the substance will dissolve in water or not.

2. Students in the middle grades will be able to distinguish between

concentration and solubility when conditions such a temperature change.

3. Students in the upper grades will be able to tell concentration in a

mathematical way as part of a whole.