Our aim is too see how the solubility of a solute changes when temperature has been changed Essay
The equipment we will be using is a test-tube, a spatula, a bun, a water bath, a thermometer, a measuring cylinder, and obviously we will need the solute and water to carry out the experiment.PLANOur aim is to see how many spatulas of a solute it will take to put in water to make it a saturated solution. Our solute will be potassium chloride.The plan is to firstly get all the equipment listed above, once we have done this we can start our experiment. We first of all have to measure out 7.5ml of water in a measuring cylinder; the water then goes straight into a test-tube. Once this is done we have to change the temperature, either to 10oc, 20oc, 30oc, 40oc, or 50oc. When the water is the right temperature we can start to add the spatulas in.The method was to put one spatula of potassium chloride, which was about 0.37g, in the test-tube, with the water, and than put the bun on top and shake it for about ten or fifteen seconds, you will than stop and add another spatula of potassium chloride in, this goes on until the solvent wont dissolve the solute anymore, this is a saturated solution. After you have made the saturated solution you record the amount of spatulas it took to make the water saturated, then you do the same but with a different temperature.The whole experiment will be done twice, a preliminary experiment and a secondary experiment.Our preliminary experiment will be very rough, no one will measure how much, of the substance they will be using, to put in the test-tube.Hardly anyone will keep the same temperature all the way through the test.So the preliminary experiment will not be a fair test at all and this is why we will probably have a lot of anomalous results.Than we will do the experiment a second time but this time we will be measuring the amount of water put in, the amount of potassium chloride put in, and also the temperature of the water will be measured every 15 seconds.FAIR TESTTo keep this experiment a fair test we will have to make sure that we put the same amount of potassium chloride in the water every time we add another.We will also have to make sure that we put the same amount of water in the test-tube every time we put fresh water in.When we change the temperature to get our next result we will have to keep the temperature the same after every shake.When we shake the solution to make it dissolve, it may make the test fairer if we time the amount of time we are aloud to shake the solution.To make the experiment more accurate or to make our results more accurate, we could do the test two or three times, so we can work out the average amount of spatulas it takes to make a saturated solution.I predict that if we do not follow these rules than we will get a lot of anomalous results.PREDICTIONMy prediction is that when the solvent is a higher temperature the water will dissolve more potassium chloride than it will if the water was at a lower temperature. I think this because when anything is heated up the particles inside it move much faster and so if you heat the water up the particles inside it will move around more rapidly. If you add the potassium chloride in when the water is at a high temperature, than the solute will brake down much more faster, and much more of it.I also think that there will be maybe a pattern in the results, I know this because there always is a pattern in the results.OBSERVATIONThe experiment did work towards the plan. The apparatus was set out properly, and the right measurements of the water were made, which was 7.5ml.SUBSTANCE10oC20oC30oC40oC50oCPotassium chloride6Spatulas5Spatulas7Spatulas8Spatulas9SpatulasAs you can see the results do not appear right on the table. This is because some mistakes were made. Mistakes were made mainly because this was the results of our preliminary experiment, which not very accurate at all. The results of our secondary experiment is below:TEMP (DEGREES CELSIUS)SPATULASPOTASSIUM CHLORIDE (g)1072.592072.5930134.8140103.750114.07You can see that the second table is more accurate but you can also still see that there are many anomalous results.CONCLUSIONAfter doing this experiment I can conclude that my explanation and prediction was correct.When you look at the results table you can see that my prediction was right. My prediction was that if you made the temperature of the solvent higher than the solvent could dissolve more spatulas of potassium chloride. This actually may not look clear on the results table because we did have quiet a few anomalous results.My explanation was that when you make a liquid higher in temperature the molecules move faster and so break down the solute much more quickly.You can see a pattern in both the preliminary results and secondary results. The pattern is if you add a temperature of 10oC, one more spatula of potassium chloride can be dissolved in the water. This supports my prediction about there being a pattern in the results.EVALUATIONThe procedure that was not perfect planned but the way we did it the experiment was also very wrong.We were supposed to measure out 7.5ml of water out, we did this alright but it could have been more accurate, by maybe using more accurate equipment.We were also supposed to measure out 0.37g of potassium chloride, sugar, salt, or copper sulphate, but no one measured if there solute was exactly 0.37g. in our group we just dumped in on spatula of potassium chloride in the water. So when we put the potassium chloride in the water, we were putting different amounts in.We all had to keep the temperature the same while we were going through the experiment but this was almost impossible to do, even though we did put the test-tube back into the water bath when the temperature decreased.All these mistakes lead to anomalous results. You can tell easily by looking at the table that we weren’t very accurate at recording the results.Even though there are many anomalous results you can see easily that the evidence is reliable. If you look at the table and exchange the anomalous number with the correct one you can see a simple pattern in both the preliminary and secondary results.We could make some big improvements to the procedure to make the experiment more fair and accurate.I have already said that we could use more accurate equipment.We could also record more temperatures so we get a better understanding of how many spatulas, more can just 5oc add.Also if everyone in the class did the experiment on the same substance the results will be more reliable because you can work out an average between everyone’s results.