Chemistry practical

Temperature change in neutralisation

Add acid to alkali in a polystyrene cup, 5 cm³ at a time, plot temperature against volume, and find the end point and the concentration of the alkali.

What you will do

1. 01Read the starting temperature of the 25.0 cm³ of sodium hydroxide in the polystyrene cup.
2. 02Measure 5.0 cm³ of hydrochloric acid in the measuring cylinder and pour it into the cup.
3. 03Stir, and record the highest temperature reached.
4. 04Repeat until 40 cm³ of acid have been added.
5. 05Plot temperature against volume of acid, draw two straight lines through the rising and falling points, and read where they cross.
6. 06Use the volume at the crossing point to calculate the concentration of the sodium hydroxide.