Concentrations of solutions

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Solutions

saturatedunsaturat

ed

with maximu

m amount of solute

less solute

than the maximu

m amount

Solutions

concentrated diluted

with large

amount of

dissolved solute

with small

amount of

dissolved solute

Add more soluteLessen the solvent

How is a concentrated solution prepared?

Lessen the solute

Add more solvent

How is a diluted solution prepared?

Fruit juices sold in grocery stores are usually concentrated solutions. How is a diluted solution prepared out of these?

Case Analysis

percent by volume = amount of solute in a given volume of solution expressed as grams solute per 100 milliliter of solution (g/mL)

percent by mass = amount of solute in a given mass of solvent expressed as grams solute per 100 grams of solution

How can the concentration of a solution be expressed quantitatively?

70 mL of ethyl

alcohol in 100 mL water

Concentration of Common Materials

What does this label mean?

5 grams of acetic acid in

100 grams of vinegar

Agua oxinada, a common antiseptic, is usually seen as 3% solution. What does that mean?

karat – used to express the concentration of solid solutions, especially gold jewelries

pure gold = 24 karat

Concentration of Solid Solutions

percent by mass = amount of solute in a given mass of solvent expressed as grams solute per 100 grams of solution

What is the concentration of an 18-karat gold?

percent by mass = mass solute in grams mass solution in grams

percent by mass = 18 karat 24 karat

x 100 = 75%

Therefore, an 18-karat gold is 75% gold!

% by mass = (14/24)x100 = 58.3%

How much gold is found in a 14-karat gold?

50 mL rubbing alcohol x 70 mL ethyl alcohol

How many mL of ethyl alcohol is present in a 50-mL bottle of 70% rubbing alcohol?

100 mL rubbing alcohol

35 mL ethyl alcohol

200 mL (40/100) = 80 mL

How many mL of ethyl alcohol is present in a 200-mL bottle of 40% rubbing alcohol?

5.4 grams x (75/100) = 4.05 grams copper

A one-peso coin has a mass of 5.4 grams. How many grams of copper are in a one-peso coin containing 75% copper by mass?

How will you prepare a 0.2 g/mL sugar solution?

20 grams sugar

100 mL water

+

20 grams / 100 mL = 0.2 g/mL

A group of students were able to gather the following data and observations after dissolving sugar in 100 mL of water.

Step Amount of Solute added

Observations

1 2 grams After stirring, sugar dissolves completely.

2 2 grams After stirring, sugar dissolves completely.

3 2 grams After stirring, sugar dissolves completely.

4 2 grams After stirring, sugar dissolves completely.

5 2 grams After stirring, some sugar is seen at the bottom of the container

Move exam quiz covering Activities 1, 2 and 3.

Prepare a ½ sheet of paper cut lengthwise. No need to bring a calculator during the test. Calculators will be available at the stations.

Good luck!

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