2. What is themaximum amountof salt that willcompletely
dissolvein a cup of water?
3. Procedure:1. Put 20 mL of water in a small clear transparent
bottle. Add teaspoon of salt and stir until all the salt
dissolves.2. To the salt solution in step #1, add teaspoon salt, a
small portion at a time and stir the solution to dissolve the salt.
At this
4. 3. Add teaspoon of salt to the salt solution in step #2 and
stir the solution. At this point, you have added one and teaspoons
of salt.4. Continue adding teaspoon salt to the same cup until the
added salt no longer
5. Q1. How many teaspoons of sugar did you add to 1 cup of
water until the sugar no longer dissolves? __________NOTE: In this
step, you willobserve that there is alreadyexcess sugar which did
notdissolve.Q2. What is the maximum
6. In this activity, you have observed that there is a maximum
amount of solute that can dissolve in a given amount of solvent at
a certain temperature. What do you think is it called? -SOLUBILITY
(of the solute)
7. The solution that contains the maximum amount of solute
dissolved by a given amount of solvent is called a-saturated
solution. If you add more solute to the solvent, it will no longer
dissolve. The solution has reached its saturation point. The
presence of an excess solid which can no longer dissolve is an
8. Is there any containerwhere all solidsdissolved?
Whichcontainer is this?
9. A solution is unsaturatedwhen it contains lesssolute than
the maximumamount it can dissolve at agiven temperature.
10. A more measurable way to find out the solubility of a
solute is to determine the maximum amount that can be dissolved in
100 g of solvent at a specific temperature. There are available
data from chemistry books that give the solubility of common
solutes at particular temperatures. Figure 2 shows the solubility
of table salt at
11. Concentration of SolutionsThe concentrationdescribes the
relativeamounts of soluteand solvent in agiven volume of
12. Observe thedemonstration.
13. Describe the concentrationsof solutions qualitatively
(bysimply observing theirappearance) andquantitatively (by
comparingthe number of drops pervolume of water).
14. From Part 1 of the demonstration, you were able to describe
the solutions as having quantitative concentrations of 1 drop/50 mL
and 10 drops/50 mL. Qualitatively, you were able to distinguish the
bottle with 10 drops/50 mL more concentrated (darker) than the
bottle with 1 drop/50 mL.
15. When there is a large amount of dissolved solute for a
certain volume of solvent, the solution is-concentrated.A solution
that has a small amount of dissolved solute in comparison to the
amount of
16. Now that you have distinguished dilute from concentrated
solutions qualitatively and quantitatively from your teachers
demonstration, you can express concentration in other ways such as:
(1) percent by volume, which is the amount of solute in a given
volume of solution expressed as grams solute per 100 millliter of
solution (g/100 mL), and (2) percent by mass, which is the amount
of solute in a given mass of solvent expressed
17. Labels of products sold often show the concentrations of
solutes expressed as percent (%) by volume or mass. The alcohol
used as a disinfectant is a solution of 70% ethyl or isopropyl
alcohol, meaning 70 mL alcohol. There are also solutions sold as
40% ethyl or isopropyl alcohol. Vinegar is often labeled as 5%
acidity, which means that it contains 5 grams of acetic acid in 100
g of vinegar. The common antiseptic, agua oxinada is a
18. The concentration of solid solutions, like gold jewelry, is
expressed as karat. Pure gold is referred to as 24 karats. Jewelry
that is said to be 18 karats contains 18 grams of gold for every 24
grams of the material, 6 grams consist of the other metal like
copper or silver. This material has a concentration of 75% gold,
that is, [18/24(100)]. A 14 karat (14K) gold contains 14 grams gold
and 10 grams of another metal, making it 58.3% gold.
19. The following sample problems show you that there is a way
to know the exact ratio of solute to solvent, which specifies the
concentration of a solution. Sample problem 1How many mL of ethyl
alcohol are present in a 50 mL bottle of rubbing alcohol?
20. Calculation for sample problem 1 Since rubbing alcohol
contains 70% ethyl alcohol, it means that 100 mL of rubbing alcohol
contains 70 mL ethyl alcohol. So, the following calculations show
that in 50 mL of rubbing alcohol, there is 35 mL ethyl alcohol. The
water content is most likely more. There is no easy way to
determine but it would be incorrect
21. Sample problem 2A one peso coin has a mass of 5.5 grams.
How many grams of copper are in a one peso coin containing 75%
copper by mass?
22. Calculation for sample problem 2 75% by mass means 75 grams
of copper in 100 grams of one peso coin. So, a 5.5 grams coin
contains, 75 g copper x 5.5 g coin = 4.1 g copper 100 g coin