Calculate concentration

Calculate concentration

By Azhar Hj Abu Bakar

Concentration of a solution

​Lesson Objective:

1) Calculate concentration as mass of solute dissolved in a given volume of solution.

2) ​Use g/dm³ as unit of concentration.

​Lesson Objective:

1) Calculate concentration as mass of solute dissolved in a given volume of solution.

​Lets recall what solute and solution is.

​

Sugar dissolves in water. They now become sugar solution.

​Sugar is the solute - as it dissolves.

Water is the solvent - where the solute dissolves.

Together they become solution.​

​

Press NEXT to try the quiz​

Multiple Choice

Salt dissolves in water to produce salt solution.

Which one is the solute?

• Salt

• Water

• Salt solution

• None of the option

​Lesson Objective:

1) Calculate concentration as mass of solute dissolved in a given volume of solution.

​Which of the following is sweeter?

​

Adding 5 gram sugar to 100 mL water OR

Adding 3 gram sugar to 50 mL water?​

​

​

Press NEXT and take a guess!​

Multiple Choice

Salt dissolves in water to produce salt solution.

Which one is the solution?

• Salt

• Water

• Salt solution

• None of the option

Poll

Which one is sweeter?

Have a guess!

• 5 gram sugar

  in 100 mL of water

• 3 gram sugar

  in 50 mL of water

​Lesson Objective:

1) Calculate concentration as mass of solute dissolved in a given volume of solution.

To know the answer, we have to find out which one have

more sugar per unit volume.​ Let us calculate:​

​

​

​

​​

0.06 g/mL is sweeter because it contain more sugar​ per unit volume.

This is called concentration.​

Press NEXT for some quiz!​

5 gram sugar, 100 mL water:

so 5 g / 100 mL = 0.05 g/mL​

3 gram sugar, 50 mL water:

so 3 g / 50 mL = 0.06 g/mL​

Multiple Choice

What does concentration means in Chemistry?

• Amount of solute dissolved per unit volume of solvent

• Amount of solvent that dissolves the solute

• The amount of salt solution produced

Multiple Choice

How do we calculate concentration?

• mass of solute / volume of solvent

• mass of solvent / volume of solute

• volume of solute / mass of solvent

• volume of solvent / mass of solute

Multiple Choice

10 gram of salt is dissolved in a 60 mL of water.

What is the concentration of the salt solution?

• 0.6 g/mL

• 6 mL/g

• 0.6 mL/g

• 6 g/mL

​Lesson Objective:

2) ​Use g/dm³ as unit of concentration.

​Earlier example we use mL as the volume of solvent.

But for concentration, we have to use dm³ as unit for volume.​

​

Let us learn some other units use to measure volume first.​

1 mL (milliliters) = 1 cm³​

​1 L (liters) = 1 dm³

​therefore: 1 L = 1000 mL OR 1 cm³ = 1000 dm³

​also: 1 mL = 0.001 L OR 1 dm³ = 0.001 cm³

Press NEXT to do practice questions

Multiple Choice

What is the unit of concentration?

• g/mL

• g/cm³

• g/dm³

• g/L

Multiple Choice

1 L is equal to ...

• 1 mL

• 1 cm³

• 1 dm³

Multiple Choice

1 mL is equal to ...

• 1 mL

• 1 cm³

• 1 dm³

Multiple Choice

1 L is equal to ...

• 0.001 mL

• 1000 cm³

• 1000 dm³

Multiple Choice

1 mL is equal to ...

• 1000 L

• 0.001 dm³

• 0.001 cm³

​Lesson Objective:

2) ​Use g/dm³ as unit of concentration.

​Let us do some calculation:

​

​

​

​

​

​

​

Press NEXT to do practice questions

5 gram sugar, 100 mL water:

convert mL into dm³​

​1 mL = 0.001 dm³

so: 100 mL = 0.1 dm³

​

concentration = 5 g / 0.1 dm³ = ​50 g/dm³

3 gram sugar, 50 mL water:

convert mL into dm³​

​1 mL = 0.001 dm³

so: 50 mL = 0.05 dm³

​

concentration = 3 g / 0.05 dm³ = ​60 g/dm³

Multiple Choice

20 gram sugar dissolved in 2 liters of water.

Convert 2 liters to dm³

• 2000 dm³

• 2 dm³

• 0.002 dm³

Multiple Choice

20 gram sugar dissolved in 2 liters of water (2 dm³).

Calculate concentration of sugar solution.

• 10 g/dm³

• 0.1 g/dm³

• 0.01 g/mL

Multiple Choice

6 gram salt dissolved in 30 mL of water.

Convert 30 mL to dm³

• 30 dm³

• 0.03 dm³

• 30,000 dm³

Multiple Choice

6 gram salt dissolved in 30 mL of water (0.03dm³).

Calculate concentration of salt solution

• 0.005 g/dm³

• 200 g/dm³

• 0.2 g/mL

Multiple Choice

8 gram salt dissolved in 100 mL of water.

Calculate concentration of salt solution

• 0.08 g/dm³

• 80 g/dm³

• 0.08 g/mL

• 80 g/mL

Ask yourself - did you learn this today?

​Lesson Objective:

1) Calculate concentration as mass of solute dissolved in a given volume of solution.

2) ​Use g/dm³ as unit of concentration.

​

- THE END -​