A student transfers 50.0 cm3\mathrm{cm^{3}}cm3 of magnesium chloride solution to a volumetric flask. The student adds distilled water until the volume of the solution is 200 cm3\mathrm{cm^{3}}cm3.
The student says:
"The concentration of magnesium chloride is now four times its original value."
Explain why the student is wrong.
152 exam-style questions on OCR GCSE Chemistry 5.1 Monitoring chemical reactions, covering 5.1.1 The technique of titration, 5.1.2 Theoretical mass, percentage yield and atom economy, 5.1.3 Concentration of a solution in mol/dm3, 5.1.4 Concentration calculations and titration results, 5.1.5 Molar gas volume and volumes of gases in reactions, and 5.1.6 Choosing a reaction pathway. Each one has a worked solution and a mark scheme showing where the marks go.