2 Specific Latent Heat of Vaporisation of Water RA 61 DEMO Aim To calculate the latent heat of vaporisation of water Equipment: Kettle, mass balance, stopclock Method: 1547 Figure 2 Boil a kettle of water Measure the mass of the kettle and water Reboil the kettle with the lid open for 2-3 minutes - record the time. (Use mains switch to switch off and/or use a rod to jam switch-off mechanism, to avoid close proximity to kettle) Measure the final mass of the kettle and water Calculate the electrical energy used from the power rating of the kettle using P=E/t. Calculate the mass evaporated Calculate the latent heat of vapourisation using: E₁ = ml₁ m=1219.73g Mafter = 908. 631g 1850-2200W 5 mins

2 Specific Latent Heat of Vaporisation of Water RA 61 DEMO Aim To calculate the latent heat of vaporisation of water Equipment: Kettle, mass balance, stopclock Method: 1547 Figure 2 Boil a kettle of water Measure the mass of the kettle and water Reboil the kettle with the lid open for 2-3 minutes - record the time. (Use mains switch to switch off and/or use a rod to jam switch-off mechanism, to avoid close proximity to kettle) Measure the final mass of the kettle and water Calculate the electrical energy used from the power rating of the kettle using P=E/t. Calculate the mass evaporated Calculate the latent heat of vapourisation using: E₁ = ml₁ m=1219.73g Mafter = 908. 631g 1850-2200W 5 mins