Determine enthalpy change of single displacement reaction between zinc and copper sulphate

Introduction:

Zinc is placed at a higher position in the activity series compared to copper. Hence zinc can displace copper from a solution of copper sulphate. During this displacement reaction, heat evolved can be calculated in kJmol^-1. The amount of heat evolved can be used to determine the relative position of metals in the activity series.

Procedure:

· Pipette 25.0mL of 1.0 mol.dm^-3 CuSO₄ into a styrofoam cup.

· Weigh around 1.0 g of zinc powder and record the exact mass.

· Put the temperature probe through the hole in the lid, stir and record the temperature to the nearest 0.1^oC every half minute for 2.5 minutes.

· At precisely 2.5 minutes, add the zinc powder to the cup.

· Continue stirring and record the temperature till there are at least 5 readings where the temperature has dropped from the previous reading.

Data Collected

Analysis

1 Calculate the heat of the reaction by using q = mcDT,
c = 4.18 Jg^-1°C^-1 and DT is the change in temperature.

1 Convert the heat of the reaction (in joules) to kJ mol^–1 of limiting reagent

2 Show the propagation of uncertainties in your calculations

Discussion:

Evaluate your experiment. What assumptions did you make?

The literature value for this displacement reaction is -218kJmol^-1. Calculate the % error and mention some sources of error and how precise (replicable) your results were. (the class results)