This tool works through concentration and dilution calculations step by step. It converts the units first, then uses c = n ÷ V or c₁V₁ = c₂V₂, and ends with a unit check.
Free tool · Chemistry
Concentration and dilution tutor
You mix up the two volume units and the concentration never comes out right.
Everything you enter stays on this device.
Who is this tool for?
It helps a Chemistry student who knows the formulas but loses marks on units, or who is not sure which quantity stays the same in a dilution.
How do I use it?
- Choose what you want to find, such as concentration, moles, volume or a dilution quantity.
- Fill in the boxes. Pick cm³ or dm³ beside each volume.
- Press “Work it out”.
- Read the unit conversion, the relationship and the answer.
- Read the note on what stays the same.
How does it work?
Every volume is changed to dm³ first, dividing cm³ by 1000. Then the tool applies c = n ÷ V, n = c × V or V = n ÷ c.
For dilution, it finds the moles of solute in the original portion, which do not change. It then divides by the final volume or solves for the missing quantity. It refuses a final concentration that is higher than the original one.
What does a worked example look like?
Suppose 25 cm³ of 2.0 mol/dm³ solution is diluted to 500 cm³. Convert first: 25 cm³ is 0.025 dm³ and 500 cm³ is 0.5 dm³.
The moles of solute are 2.0 × 0.025 = 0.05 mol. The final concentration is 0.05 ÷ 0.5 = 0.1 mol/dm³. The solvent added is 500 − 25 = 475 cm³, if the volumes add.
What can the tool not tell you?
It is a calculation tutor and not guidance for preparing solutions. It does not work out pH, and it does not assume an acid is strong or weak.
It also assumes the solute does not react with the solvent. Check your own question for any other conditions.
Where does this connect to the lessons?
Start with calculating concentration from supplied data. The dilution idea is in explaining why dilution changes concentration but not the original solute amount.
To separate concentration from strength, read distinguishing strength from concentration. Then try the acids, bases and salts practice.
For lessons with a teacher, see Chemistry tuition and the one-hour trial class (from RM50).
Common questions
Why must volume be in dm³ for concentration?
Concentration in mol/dm³ means moles per dm³ of solution. If the volume is in cm³, divide by 1000 first. Skipping this gives an answer 1000 times too large, and it is the commonest slip in these questions.
Why does the amount of solute stay the same in dilution?
Adding solvent spreads the same particles of solute through a larger volume. The moles of solute do not change, so c₁V₁ = c₂V₂. Only the concentration falls because the volume rises.
Is concentration the same as acid strength?
No. Concentration is how much solute is in a volume. Strength is how far an acid ionises in water. This tool only does concentration and dilution arithmetic and makes no assumption about strength or pH.
If concentration questions still go wrong after the steps look clear here, a teacher can go through your own working with you in a one-to-one lesson.
- Online one-to-one lessons for your child with an experienced teacher.
- Your first class is a one-hour trial, from RM50. The fee is agreed before you book.
- Happy with the teacher? Continue with lessons of about 1.5 hours. If not, ask for another teacher.