Answer to Question #175640 in General Chemistry for John

Question

Experiment to find the enthalpy change for the reaction

Carry out a risk assessment using the template provided in Appendix 1.

2. Pipette 25 cm cubed of the copper sulphate solution into a polystyrene cup.

3. Weigh about 6 g of zinc powder in the weighing bottle. (since this is in excess

there is no need to be accurate).

4. Put the thermometer through the hole in the lid,stir and record the

temperature to the nearest 0.1 oC every half minute for 2.5 minutes.

5. At precisely three minutes,add the zinc powder to the cup.

6. Continue stirring and record the temperature for an additional 6 minutes to

complete the results table on the following page.

Calculate ∆H for quantities used 

Calculate ∆H for 1 mol of each Calculate % error

Comparison w/ accepted value Reasons for difference

Answer 1

Add together the heats of formation for the products,

which is –110.53 kJ/mol + 0 kJ/mol = –110.53

1.15 g caused the temperature increase of 24 °C: 20.100 kJ / 0.013 mol = 1,510 kJ/mol