Determining Enthalpy Change of a Displacement Reaction
Determining an enthalpy change of a displacement reaction
Aim:
To determine the enthalpy change for the displacement reaction between zinc powder and copper (II) sulphate solution.
Zn (s) + Cu2+ (aq) → Cu2+ (s) + Zn2+ (aq)
Theory:
For the displacement reaction, an excess amount of zinc powder is added to the measured amount of aqueous copper (II) sulphate. The temperature change over a period of time has to be measured and thus, the enthalpy change for the reaction can be measured.
The equation of the above reaction is:
Zn (s) + Cu2+ (aq) → Cu2+ (s) + Zn2+ (aq)
Apparatus: * * Safety spectacles * Polystyrene cup with lid * Pipette, 25 cm3 * Pipette filler * Weighing bottle * Spatula * Balance * Thermometer, 0-100∘C (0.1∘graduations) * Timer * Beaker, * 100 cm3 (X2) * 600 cm3 (X1) * 500 cm3 (X1)
Chemicals: * Zinc powder * Copper (II) sulphate solution, 1.00M
Hazards: Toxic Harmful
Procedures: 1) The pipette was washed with water first and then with copper (II) sulphate solution. 2) 25 cm3 of copper (II) sulphate solution was transferred in the polystyrene cup. 3) About 6 g of zinc powder was weighed in the weighing bottle. Since the zinc powder was in excess, there was no need to be accurate. 4) Thermometer was put through the hole in the lid, stirred and the temperature was recorded to the nearest 0.1∘C every half minute for 2½ minutes. 5) At precisely 3 minutes, the weighed zinc powder is transferred in the polystyrene cup. 6) Stirring was continued and temperature was recorded for an addition of 6 minutes. 7) The results were tabulated and a graph of change in temperature of the solution at different time intervals was plotted.
Results: Time (min) | 0.0 | 0.5 | 1.0 | 1.5 | 2.0 | 2.5 | 3.0 | 3.5 | 4.0 | 4.5 | Temperature (∘C) | 20.4 | 20.4 | 20.4 | 20.4 | 20.5 | 20.5 | – | 63.4 | 65.5 | 65.7 | Time (min) | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | Temperature
Aim:
To determine the enthalpy change for the displacement reaction between zinc powder and copper (II) sulphate solution.
Zn (s) + Cu2+ (aq) → Cu2+ (s) + Zn2+ (aq)
Theory:
For the displacement reaction, an excess amount of zinc powder is added to the measured amount of aqueous copper (II) sulphate. The temperature change over a period of time has to be measured and thus, the enthalpy change for the reaction can be measured.
The equation of the above reaction is:
Zn (s) + Cu2+ (aq) → Cu2+ (s) + Zn2+ (aq)
Apparatus: * * Safety spectacles * Polystyrene cup with lid * Pipette, 25 cm3 * Pipette filler * Weighing bottle * Spatula * Balance * Thermometer, 0-100∘C (0.1∘graduations) * Timer * Beaker, * 100 cm3 (X2) * 600 cm3 (X1) * 500 cm3 (X1)
Chemicals: * Zinc powder * Copper (II) sulphate solution, 1.00M
Hazards: Toxic Harmful
Procedures: 1) The pipette was washed with water first and then with copper (II) sulphate solution. 2) 25 cm3 of copper (II) sulphate solution was transferred in the polystyrene cup. 3) About 6 g of zinc powder was weighed in the weighing bottle. Since the zinc powder was in excess, there was no need to be accurate. 4) Thermometer was put through the hole in the lid, stirred and the temperature was recorded to the nearest 0.1∘C every half minute for 2½ minutes. 5) At precisely 3 minutes, the weighed zinc powder is transferred in the polystyrene cup. 6) Stirring was continued and temperature was recorded for an addition of 6 minutes. 7) The results were tabulated and a graph of change in temperature of the solution at different time intervals was plotted.
Results: Time (min) | 0.0 | 0.5 | 1.0 | 1.5 | 2.0 | 2.5 | 3.0 | 3.5 | 4.0 | 4.5 | Temperature (∘C) | 20.4 | 20.4 | 20.4 | 20.4 | 20.5 | 20.5 | – | 63.4 | 65.5 | 65.7 | Time (min) | 5.0 | 5.5 | 6.0 | 6.5 | 7.0 | 7.5 | 8.0 | 8.5 | 9.0 | 9.5 | Temperature