Phase Two Titration Year 10 EEI by Mr H Graham Volumetric analysis is; A type of chemical analysis which depends on the accurate measurement of solution volumes A titration is a form of volumetric analysis

Phase Two Titration Year 10 EEI by Mr H Graham

Phase Two This Friday we will carry out a titration using a 2g sample of the white powder mix The white powder contains sodium carbonate. This will be titrated with a standard (known concentration) hydrochloric acid solution. By measuring the volume accurately and by using n = cV we can find the number of moles of hydrochloric acid reacting and by using the reaction ratio find the number of moles of carbonate in the original mix

Phase Two Titration Year 10 EEI by Mr H Graham BUT! WHAT DOES A TITRATION LOOK LIKE?

Phase Two Titration Year 10 EEI by Mr H Graham TITRATION ANIMATION REQUIRES WEB LINK HERE

Phase Two Titration Year 10 EEI by Mr H Graham Titration equipment pipette accurately measures smaller volumes (25mL) burette a graduated tube with tap. Used to measure volumes of solutions during a titration Research, How they are used.

Phase Two Titration Year 10 EEI by Mr H Graham Titration equipment volumetric flask accurately measures a set volume (100mL) pipette filler a device that is used to draw solutions safely into a pipette Research, How they are used.

Phase Two Titration Year 10 EEI by Mr H Graham Procedure Dissolve two grams of white powder in about 40mL of H 2 O Pour this into a 100mL volumetric flask. Add distilled water so that you get up to the 100mL mark. This solution has an unknown concentration. Set up a clean burette using a burette stand. Use a funnel and fill this with the hydrochloric acid solution (known concentration 0.1M) Pipette 20mL of the white powder solution into a conical flask. Add 4 drops of methyl orange indicator (this will turn yellow) TITRATE by adding the acid solution from the burette into the conical flask. You will notice a pink colour appearing as the acid is added. Proceed slowly STOP and RECORD the volume of acid When the indicator changes to all PINK (END POINT) USE n =c V to find the number of moles of acid added COPY THIS

Phase Two Titration Year 10 EEI by Mr H Graham white powder mix has high pH at the start of the titration by adding acid from the burette the pH drops. The indicator changes when the reaction is complete

Phase Two Titration Year 10 EEI by Mr H Graham

The unknown Na 2 CO 3 is titrated against an known HCl solution. 20mL of the carbonate is placed in the conical. The known (0.1M) HCl in the burette. An average titration reading of ? is obtained. What is the concentration of the carbonate solution? 2H + + CO 3 2- = CO 2 + H 2 O Consider your titration, we know three key things we need to calculate the acid concentration a simplified form of the equation, notice the 2 : 1 ratio

Phase Two Titration Year 10 EEI by Mr H Graham 2HCl + Na 2 CO 3 2NaCl +CO 2 + H 2 O Consider your titration, we know three key things we need to calculate the acid concentration HCl = 0.1M volume ? burette reading Na 2 CO 3 conc unknown volume = 20mL (0.02L) Find moles of HCl Find moles of carbonate in 20mL of solution (half moles of HCl) Find how many moles of carbonate in 100mL volumetric flask This is the number of moles in 2g of white powder Find the number of moles in 5g of powder Find mass of Na 2 CO 3 in 5g 2 1