1. { Solutions (1.5) Year 11 DP Chemistry Rob Slider

2. Definitions Solute Solute: the substance that dissolves in another substance (solvent) to create a solution Solvent Solvent: the substance (usually a liquid) that dissolves another substance (solute) to form a solution Solution Solution: the homogeneous mixture of one or more solutes in a solvent.

3. Concentration Concentration Concentration: the amount of solute per volume of solution. Expressed as: g. dm -3 mol. dm -3 (M) mol. dm -3 (M) If I have 25g of a substance in 500mL of solution, what is the concentration? Answer: 50 g. dm -3 What if I have 58.5 g of NaCl in 500mL? What is the concentration in mol. dm -3 or M? 2M

4. Dilutions C 1 V 1 = C 2 V 2 When diluting a solution, we change the concentration and the volume, but the number of moles of the solute (n) does not change (i.e. n = cv) Example: How much 10M HCl do we need to make up 1L of 2.5M HCl? Answer: C 1 =10M, C 2 = 2.5M, V 2 =1000mL (10M)(V 1 ) = (2.5M)(1000mL) V 1 = 250mL Notice that the # of moles (n) stays the same

5. Exercises 1.How would you prepare 1dm 3 of 2M NaCl? 2.Which is greater? a)1M hydrogen gas b)2 g. dm -3 hydrogen gas 3.I have a litre of 5M H 2 SO 4 and I want to make up some 2M H 2 SO 4. Explain how can this be done?