1. Calculating the Number of Moles in a Solution
Learning Objectives:
To be able to calculate the number of moles of a solute in a solution, given the concentration of the solution and the volume of the solution.

2. Calculating Amounts You use this triangle in the same
way as you did before, to calculate
the number of moles of a substance
that you have.
Cover over the one you want
to know and then the calculation
you need will be left.
number of moles
concentration
volume
(in dm3)

3. Great! You wanted to find the number of moles, so...
Example
If you want to know the number of
moles of a solute in a solution...
number of moles
concentration
volume
(in dm3)
Reset
Click on the variable you want to find out in the triangle
Great! You wanted to find the number of moles, so...
number of moles = concentration x volume (in dm3)
No of moles
This would give Volume (dm3) =
Concentration
No of moles
This would give Concentration =
Volume (dm3)

4. This would give Volume (dm3) = Concentration No of moles
Example
If you want to know the number of moles of a solute where there are 500 cm3 of a 2.0 mol.dm-3 solution...
number of moles
concentration
volume
(in dm3)
Reset
No of moles
This would give Volume (dm3) =
Concentration
Is that what you needed to find out?
No of moles
This would give Concentration =
Volume (dm3)
Is that what you needed to find out?
Great! You wanted to find the number of moles, so...
number of moles = concentration x volume (in dm3)
moles = 2 x 0.5 dm3 (500 ÷ 1000) = 1.0 mol

5. A 0.5 mol.dm-3 solution has a volume of 0.2 dm3.
Questions
A 0.5 mol.dm-3 solution has a volume of 0.2 dm3.
How many moles of solute are in the solution?
Answer moles
Check
moles = Concentration x volume
= 0.5 x 0.2
= 0.1 moles
Pupils do questions and then put answer in box and check.
There are 10 questions.
A score could be given at the end.
Is there a way of randomly generating values for concentration and volume; that would be even better.

6. A 0.2 mol.dm-3 solution has a volume of 200 cm3.
Questions
A 0.2 mol.dm-3 solution has a volume of 200 cm3.
How many moles of solute are in the solution?
Answer moles
Check
moles = Concentration x volume
= 0.2 x 0.2
= 0.04 moles
Pupils do questions and then put answer in box and check.
There are 10 questions.
A score could be given at the end.
Is there a way of randomly generating values for concentration and volume; that would be even better.

7. A 0.15 mol.dm-3 solution has a volume of 0.02 dm3.
Questions
A 0.15 mol.dm-3 solution has a volume of 0.02 dm3.
How many moles of solute are in the solution?
Answer moles
Check
moles = Concentration x volume
= 0.15 x 0.02
= moles
Pupils do questions and then put answer in box and check.
There are 10 questions.
A score could be given at the end.
Is there a way of randomly generating values for concentration and volume; that would be even better.

8. A 1.0 mol.dm-3 solution has a volume of 0.2 dm3.
Questions
A 1.0 mol.dm-3 solution has a volume of 0.2 dm3.
How many moles of solute are in the solution?
Answer moles
Check
moles = Concentration x volume
= 1.0 x 0. 2
= 0.2 moles
Pupils do questions and then put answer in box and check.
There are 10 questions.
A score could be given at the end.
Is there a way of randomly generating values for concentration and volume; that would be even better.

9. A 0.25 mol.dm-3 solution has a volume of 10 cm3.
Questions
A 0.25 mol.dm-3 solution has a volume of 10 cm3.
How many moles of solute are in the solution?
Answer moles
Check
moles = Concentration x volume
= 0.25 x 0.01
= moles
Pupils do questions and then put answer in box and check.
There are 10 questions.
A score could be given at the end.
Is there a way of randomly generating values for concentration and volume; that would be even better.

10. A 0.01 mol.dm-3 solution has a volume of 25 cm3.
Questions
A 0.01 mol.dm-3 solution has a volume of 25 cm3.
How many moles of solute are in the solution?
Answer moles
Check
moles = Concentration x volume
= x 0.025
= moles
Pupils do questions and then put answer in box and check.
There are 10 questions.
A score could be given at the end.
Is there a way of randomly generating values for concentration and volume; that would be even better.

11. A 0.075 mol.dm-3 solution has a volume of 0.2 dm3.
Questions
A mol.dm-3 solution has a volume of 0.2 dm3.
How many moles of solute are in the solution?
Answer moles
Check
moles = Concentration x volume
= x 0. 2
= moles
Pupils do questions and then put answer in box and check.
There are 10 questions.
A score could be given at the end.
Is there a way of randomly generating values for concentration and volume; that would be even better.

12. A 0.1 mol.dm-3 solution has a volume of 2.5 dm3.
Questions
A 0.1 mol.dm-3 solution has a volume of 2.5 dm3.
How many moles of solute are in the solution?
Answer moles
Check
moles = Concentration x volume
= 0.1 x 2.5
= 0.25 moles
Pupils do questions and then put answer in box and check.
There are 10 questions.
A score could be given at the end.
Is there a way of randomly generating values for concentration and volume; that would be even better.

13. A 0.1 mol.dm-3 solution has a volume of 250 cm3.
Questions
A 0.1 mol.dm-3 solution has a volume of 250 cm3.
How many moles of solute are in the solution?
Answer moles
Check
moles = Concentration x volume
= 0.1 x 0.25
= moles
Pupils do questions and then put answer in box and check.
There are 10 questions.
A score could be given at the end.
Is there a way of randomly generating values for concentration and volume; that would be even better.

14. A 0.5 mol.dm-3 solution has a volume of 0.02 dm3.
Questions
A 0.5 mol.dm-3 solution has a volume of 0.02 dm3.
How many moles of solute are in the solution?
Answer moles
Check
moles = Concentration x volume
= 0.5 x 0.02
= 0.01 moles
Pupils do questions and then put answer in box and check.
There are 10 questions.
A score could be given at the end.
Is there a way of randomly generating values for concentration and volume; that would be even better.