Revision notes · Quantitative chemistry
Using concentrations of solutions in mol/dm3
Using concentrations of solutions in mol/dm34.3.4
Definition: The concentration of a solution in mol/dm3 is the amount of solute in moles dissolved per unit volume of solution.
Concentration measures how many moles of a dissolved substance are contained in a set volume of liquid.
- •The formula linking concentration, amount, and volume is concentration (mol/dm3) = amount (mol) ÷ volume (dm3).
- •To convert a volume from cm3 to dm3, you must divide the volume in cm3 by 1000.
- •To convert concentration from g/dm3 to mol/dm3, divide the concentration in g/dm3 by the solute's relative formula mass (Mr).
- •In a titration, the known volume and concentration of one solution are used alongside the balanced equation to calculate the concentration of an unknown solution.
⚠️ Common mistake: Forgetting to convert the volume from cm3 to dm3 by dividing by 1000 before using the concentration formula.
🧠 Remember: Moles = Concentration × Volume (where volume must always be in dm3).
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