Write a SOP (standard operating procedure) for doing a titration Bell Work Write a SOP (standard operating procedure) for doing a titration Do not use your books Hints – diagram, use known/unknown/ tips

ASE Presentation for New Users Big Picture Assessment at AS Unit F331 Chemistry for Life Unit F332 Chemistry of Natural Resources Unit F333 Chemistry in Practice (internal assessment) Elements of Life Developing Fuels Elements from the Sea The Atmosphere Polymer Revolution Five practical skills 15% of A level 25% of A level 10% of A level Written paper 1 hr 15 min Written paper (one question on an ‘Advance Notice’ passage) 1 hr 45 min Internal assessment of skills using materials and mark schemes provided by OCR

CI p371

Content Process Benefit Learning Outcomes Content Process Benefit Skill of carrying out a titration Calculate unknowns and percentage uncertainty Carry out a titration Help in 10% of AS grade!

ES4.1 Activity Carry out titration Put your results on the board Use the booklet to help write your results

The question: 10.0 cm3 of a solution of potassium hydroxide was titrated with a 0.10 M solution of hydrochloric acid. 13.5 cm3 of the acid was required for neutralization. Calculate the concentration of the potassium hydroxide solution. Step 1 Write down everything you know from the question. I put the one we know most about on the left   Hydrochloric Acid                                 Potassium hydroxide Volume used = 13.5 cm3                     Volume used = 10.0 cm3 Concentration = 0.10M                         Concentration = TBD TBD to be determined

Step 2 Write the BALANCED equation (or as much as you know about it).  HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)   This is necessary to check out the ratios of reactants – in this case 1:1 so we don’t have to worry about any ratios. Step 3 Calculate the Number of Moles used of the reactant you know most about. In this case the HCl(aq) The rule here is ; Number of Moles = concentration

Step 3 Calculate the Number of Moles used of the reactant you know most about. In this case the HCl(aq)   The rule here is ; Number of Moles = volume × concentration Never do cm3!

Step 4 Work out how many moles of the unknown you have used, this is where you may need to multiply up or down the number of moles, so if 1 mole of HCl needed 2 mol of potassium hydroxide, then at this point you would multiply the number of moles of HCl by 2. In this case this is unnecessary.   Number of moles of HCl = 0.0014 mol Number of moles KOH = 0.0014 mol – they react in a one to one ratio

Step 5  Work out the concentration of the potassium hydroxide. Moles of KOH (same as HCl as 1:1) – 0.0014 Volume (q) 10cm3   Concentration = 0.14 M Number of Moles = volume × concentration

CH3COOH + NaOH  H2O + NaOOCCH3 0.1M NaOH ? CH3COOH Volume 6cm3 10cm3 Balance equation No. moles = Vol dm3 x conc. ? = (6/1000) x 0.1Moles dm-3 ? = 6 x 104 Moles 1:1 ratio thus 6 x 104 Moles of acid So Conc = Moles/vol dm3 = 6 x 10 4 / (10/1000) = 0.06 Moles dm-3

Demonstrate Deduce the concentration of hydrochloric acid if 20.0cm3 is neutralised by 25.0cm3 of sodium hydroxide at 0.2oo moldm-3?

Carry out a titration? Confident with procedure? Review Carry out a titration? Confident with procedure? Confident with calculations? What to do if you’re not?

Home Learning Best Choice – Salters A level / ES Formula, equations, amount / Titrations and titration calculations Next lesson is halogen production conference – have poster with you and all 15.1-6 qs + ready to speak