Answers section
Questions 2.7(a)
Accurate measurements are extremely important in Chemistry.
- Name the two quantities we need to measure in order to prepare an aqueous solution of accurate concentration in mol/dm3.
- Which instruments and apparatus do we require?
- Which two substances do we require?
- How can we ensure that the solution we prepare is not contaminated with other substances?
Answers to Questions 2.7(a) 
- Mass (M), and volume (V)
- Electrical weighing balance, measuring cylinder, volumetric flask, beaker, wash bottle
- Water, and the substance (solute: solid or liquid) whose solution is to be prepared.
- Use distilled water, and clean apparatus.