Dissolving Heat Experiment

1353 Words 6 Pages
How the changing mass of solute effects the heat given out when dissolved in water
Aim
To investigate how the changing mass of a solute will affect the energy given out.
Introduction
Dissolving is when a solute is mixed into a solvent to form a solution. Dissolving can be either endothermic or exothermic. Endothermic reactions happen when the energy given out when bonds are broken, is greater than the energy given out when bonds are made. As more energy is used and taken in, the surroundings become colder. Dissolving is exothermic when energy is given out to its surroundings. In an exothermic reaction bonds are being made. The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to get warmer. Exothermic
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Different solvents need different amounts of energy to break their bonds, as they are made of different ions.
• Temperature of the water. The higher the temperature of the water at the start, the bigger the energy changes in dissolving when it is exothermic.
The factor that I will be looking at for this experiment is how the mass of solvent effects the temperature change.

The factor that I am choosing to investigate is how the mass of the solute affects the temperature change during dissolving. My hypothesis states that the energy given out the solution will increase the more solute that is dissolved. I also predict that every time the mass of solute is doubled the energy given out by the solution is doubled. Which variables I change which I keep same. Variables
With all the different preliminary tests, there are many independent variables that can affect the results. These include: the water temperature, the amount of solute, the beaker size, the amount of solvent, and the temperature of the surroundings. I have decided to test the mass of solute for the experiment, making this a dependent variable. The amount of solvent and the beaker size are independent variables, as I will be keeping these the same throughout the
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I have done this because, although the means go from 334.4J-1727.7J, I think it would be better if I could get a larger range for my actual experiment. The results for 0.5g had a very low temperature change, so didn’t give very good results, which is why I will be going up in intervals of 1g for the experiment. I have also decided to use 40ml of water because it doesn’t affect the temperature change too much. After testing a range of different salts, I decided to use lithium chloride as it gave a good range of results. Finally, I chose to use a polystyrene cup to hold the solution because it was an insulator and kept the heat

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