Aim: To investigate the Latent Heat of Vaporisation of water. Independent Variables: voltage / energy Dependent Variables: temperatureControlled Variables: amount of water, voltage and currentWe won't consider uncertainties here since it is a planning lab.Hypotheses:The water will heat up at a quicker rate if a lot of energy is added instead of a small amount of energy. Due to the fact that the more energy one applies to the immersion heater, the more heat it will release into the water, increasing its temperature.To find the Latent Heat of vaporisation we need to rearrange this equation:∆m depends on ...view middle of the document...
Mix significantly until the change becomes insignificant. Measure the mass of the water (total mass - mass of empty beaker). Read of voltmeter and ammeter, readings should stay constant. Do NOT add additional energy at any point during the experiment. Leave the beaker on the scale, since we are going to read off the mass of the water every 2 minutes to be able to graph ∆m vs t with fewer uncertainties. The closer the time interval, the smaller the uncertainties.iii) Start the time as soon as the water starts to boil at a constant rate (temperature is not rising any more, bubbles rising at a constant rate). Let the experiment continue for approx. 30 min. to get enough raw data. At the end of the experiment, remember to stop the time and measure the final mass of the water. Try to keep room temp. as constant as possible during the experiment (close all windows and doors to prevent draughts). By preventing temperature change in the surroundings, we prevent larger manipulation of the data by the room temp.iv) Present your data in a graph of ∆m vs t, and then draw the line of best fit. As we want to find and we know that and the gradient of the graph represents we then know that which is the same as we take the gradient out of the graph and then re-arrange the equation so that we get :Having the gradient and having V and I which are constant we can finally find the Latent Heat of Vaporization by re-arranging the equation and solve for as shown in the graph.
