Heat of Combustion Lab Essay Example for Free

Heat of Combustion Lab EssayThere be many terminates in the world and we use fuel e rattlingday in our life. However almost fuels are very useful and some are not. Usually useful fuel means the fuel that is very efficient in a small amount. To know the efficiency of each material, we measured the changes of smokestack and temperature when we burn them. And we calculated changing energy by development the equation that we learned in the class by using our measurements. And we calculated the heat of combustion to know the efficiency of the material. We also used the data leaflet value for the standard enthalpy of combustion of each material to get the errors in our experiment. Errors in our experiment were usually over 20 percent which is kind of large.Before we heated the body of water, we do the temperature of water below than 10C with ice to see the changes of temperature more efficiently. If we just heated it in normal temperature such(prenominal) as 20C, we couldnt see the changes of temperature well, and it could take more time to heat it. We also measure the changes of mass of material to see how much we burned.We put some ice in the water to make the initial temperature of water as lower than 10C. When the temperature decreased up to 10C, we took away ice from the water. later we took out the ice and fill the cylinder up to 200ml of water, the temperature was higher than 10C because the temperature of the water changed very quickly. We measured the temperature of water and then we hang the brook stop on the hanger, so the temperature might increased again during we set up all the experiment systems. So we should measure the temperature of water when we set up all the things. For example we should measure it after we turn the light on the candle wax and hang the tin can on the hanger.We measured the last(a) temperature to see the changes of the temperature. We blew out the candle when the temperature reaches 35C, and we measured the hig hest temperature reached as the final temperature. When the temperature reaches 35C, we quickly blew out the candle. However we are not accurate as the machine so we might didnt blow out it when it reaches exactly 35C. Also it was difficult to measure the highest temperature of it after we blow it out. Even though we unbroken watching it, the temperature changes so quickly, so our measurements are not correct 100%.In our experiment we didnt measure the mass of tin can. If we measure the mass of it, we could get more precise measurement compare to the standard enthalpy of combustion. Our errors are quite large, so I think one of reason is that we forgot the measure the mass of tin. So we should study and think more about the experiment before we do it. We could calculate how much heat we got by adding the changing energy of water and the changing energy of the tin can, if we measured the mass of can.At the end of the experiment, we measured the mass of candle to know how much of the m were burned. During and after we blow out the candle, some of liquid were might evaporated. Such as ethanol and butanol are volatile liquid, and the fact that the lamp was hot indicates that some of it would have evaporated. So they are burned and evaporated more after we measure the temperature. An other(a) fact that we should consider is that not only the water was being heated, but also the thermometer, stirring rod cell and the tin can were also being heated. We should consider that they were also heated, so we should measure how much heat were used to heat them. Also some other heat would have been lost round the sides of the tin can, and from the water to the atmosphere. Due to our room temperature are different from the temperature of water.The good thing that we did in our experiment is that we made some space when we set up the large metal can to surround the candle. As we make some space under the large can by putting some flat cylinder under the can, the candle burned more quickly and well. If we didnt make the space for it, air might stuck in there so it would take more time to reaches up to 35C.