Wednesday, March 6, 2019
Heat of Combustion Lab Essay
There be many burn downs in the conception and we use fuel everyday in our life. However some fuels are very useful and some are not. Usually useful fuel means the fuel that is very efficient in a atomic amount. To discern the efficiency of each material, we metrical the changes of passel and temperature when we burn them. And we reckon ever-changing energy by using the equation that we learned in the class by using our standards. And we take aimd the hot up of combustion to know the efficiency of the material. We overly used the data booklet value for the monetary standard enthalpy of combustion of each material to get the errors in our prove. Errors in our experiment were usually over 20 percent which is quite large. ahead we heated the water, we made the temperature of water below than 10C with icing to put one over the changes of temperature much efficiently. If we just heated it in normal temperature untold(prenominal) as 20C, we couldnt see the changes of tem perature well, and it could take more snip 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 shape the sign temperature of water as lower than 10C. When the temperature decreased up to 10C, we took pop out ice from the water. After 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 calculated the temperature of water and then we hang the tin can on the hanger, so the temperature might increased again during we focalise up all the experiment systems. So we should measure the temperature of water when we set up all the things. For lawsuit we should measure it after we turn the light on the candle rear and hang the tin can on the hanger.We measured the final temperature to see the changes of the temperature. We blew out the candle when the temperature reaches 35C, and we measured the highest temperatu re 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 just 35C. Also it was difficult to measure the highest temperature of it after we blow it out. flat though we kept 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 examine 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 them were burned. Dur ing and after we blow out the candle, some of liquid were might evaporated. Such as ethanol and butanol are volatile liquid, and the event 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. Another fact that we should treat is that not only the water was being heated, but also the thermometer, stirring rod 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 rhythm method of birth control 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 cracking 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 displace some flat cylinder under the can, the candle bu rned 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.