Enthalpy Change Essay

Chemistry

Aim- To determine the enthalpy change for the reaction of between cooper sulphate and zinc.

Materials Required- Calorimeter Glass Thermometer Weighing Machine Digital Stop Watch Measuring Cylinder Cuso4 . 5H2o Zinc Metal Powder Distilled Water

By adding the access amount of zinc in the constant amount of aqueous cooper sulphate and measuring the change in temperature over time, the chande in enthalpy of the reaction can be determined using calorimeter calculation.

Materials Required-

Procedure- Establish a data table that records the temperature[Celsius] and time[ seconds]. place 25.0ml of cooper sulphate from the berette into the polystyrene cup. Weigh 6g of zinc powder on a small piece of paper, although there is

Determine the enthalpy change in enthalpy change, when there are 6g of zinc powder

ΔH= M×c× △T

Cooper sulphate = 25cm3 Specific heat capacity = 4.18J g-1 Temperature change = 25-60=-35

Enthalpy change [Joules] = -[25×4.18×35] = -3,657.5

Molar enthalpy change = Enthalpy change / Solution Moles = (-3,657.5)⁄0.0025 = -1,427,000= -1427 KJ Mol-1

Determine the enthalpy change in enthalpy change, when there are 7g of zinc powder

ΔH= M×c× △T

Cooper sulphate = 25cm3 Specific heat capacity = 4.18J g-1 Temperature change = -25.5-61= -35.5

Enthalpy change [Joules] = -[25×4.18×35.5] = -3079.75

Molar enthalpy change = Enthalpy change / Solution an exothermic reaction is when the heat is given out by the system and △H is negative.

The change in temperature upon adding Zinc in a perfect situation, where no heat is lost. The gradient shows that temperature decreases when Zinc was added in it. Very steep gradient line shows the speed of the reaction at which temperature was decreasing.

There can be percentage errors and uncertainties or heat loss in surrounding while executing the experiment.

Conclusion-

The concept of displacement reaction of Zinc in cooper sulphate is exothermic, as heat is released out while reacting. A powder substance Zinc reacts faster, when it is added to cooper sulphate solution as the total surface is high. After reaching of the peak, the temperature started falling down, as the solution starts cooling down and Heat is lost in the surrounding. An ideal situation shows the change in temperature, which we can use it in calculations; It is possible that the concentration of copper sulphate was lower and therefore less zinc reacted, releasing less energy than expected. We took four different samples of zinc in order to check the difference in enthalpy. Zinc replaces cooper in cooper sulphate, because it is more reactive and it also has very low solubility. So, this is how with the help of redox reaction we determined the enthalpy change