natalia92 Posted March 7, 2011 Report Share Posted March 7, 2011 Hello everyone,Im doing a design lab on "How does temperature affect the reaction rate of decomposition of hydrogen peroxide?". The chemical formula is 2H2O2(aq) --(catalyst)--> 2H2O(l)+O2(g)I thought of controlling the temperature by placing the vessel in which the experiment will take place into a water bath. Since its exothermic, cold water will be constantly added into the water bath to keep the temperature constant(the temperature will be monitored). But there are several problems with the method because the lower part of the vessel where the reaction is taking place(im assuming) is cold, its the top part where oxygen gas is given off that is very very hot, so the water bath will need to be covering that part. And if too much water is needed to add into the water bath, it might even go over which will ruin everything. Im very very bad at coming up with methods for experiments. I just need a little hint and would be brilliant if someone can shed me some light!!! THANK YOU!!! Reply Link to post Share on other sites More sharing options...
Keel Posted March 8, 2011 Report Share Posted March 8, 2011 Hello everyone,Im doing a design lab on "How does temperature affect the reaction rate of decomposition of hydrogen peroxide?". The chemical formula is 2H2O2(aq) --(catalyst)--> 2H2O(l)+O2(g)I thought of controlling the temperature by placing the vessel in which the experiment will take place into a water bath. Since its exothermic, cold water will be constantly added into the water bath to keep the temperature constant(the temperature will be monitored). But there are several problems with the method because the lower part of the vessel where the reaction is taking place(im assuming) is cold, its the top part where oxygen gas is given off that is very very hot, so the water bath will need to be covering that part. And if too much water is needed to add into the water bath, it might even go over which will ruin everything. Im very very bad at coming up with methods for experiments. I just need a little hint and would be brilliant if someone can shed me some light!!! THANK YOU!!!Hi,An easy way to over come this is not to take the rate of reaction for the whole reaction but to take the 'initial' rate of reaction. What you can do is to limit the time of reaction to such a short period of time that it will represent the 'initial' rate of reaction say 15 seconds. This should solve your problem of the water bath being flooded with water. The heat given off won't really affect the experiemnt because its in such as short time span. So your intial rate of reaction with varing temperature will be calculated as volume of gas produced (cm3) / 15 seconds = initial rate (cm3/s).I would also like to comment on the control variables of this experiment. This may seem a nice old 'rates of reaction' design but I would like to emphasise that you are using a catalyst. Thus any variables which may affect the productivity of a catalyst (apart from temperature which is your independent variable) must be controlled. These include, heavy metal volume and concentration, volume and concentration of inhibitors, pH of the solution, and the obvious things like volume and concentration of catalyst and hydrogenperoxide.Hope this helped. 1 Reply Link to post Share on other sites More sharing options...
natalia92 Posted March 8, 2011 Author Report Share Posted March 8, 2011 Hello everyone,Im doing a design lab on "How does temperature affect the reaction rate of decomposition of hydrogen peroxide?". The chemical formula is 2H2O2(aq) --(catalyst)--> 2H2O(l)+O2(g)I thought of controlling the temperature by placing the vessel in which the experiment will take place into a water bath. Since its exothermic, cold water will be constantly added into the water bath to keep the temperature constant(the temperature will be monitored). But there are several problems with the method because the lower part of the vessel where the reaction is taking place(im assuming) is cold, its the top part where oxygen gas is given off that is very very hot, so the water bath will need to be covering that part. And if too much water is needed to add into the water bath, it might even go over which will ruin everything. Im very very bad at coming up with methods for experiments. I just need a little hint and would be brilliant if someone can shed me some light!!! THANK YOU!!!Hi,An easy way to over come this is not to take the rate of reaction for the whole reaction but to take the 'initial' rate of reaction. What you can do is to limit the time of reaction to such a short period of time that it will represent the 'initial' rate of reaction say 15 seconds. This should solve your problem of the water bath being flooded with water. The heat given off won't really affect the experiemnt because its in such as short time span. So your intial rate of reaction with varing temperature will be calculated as volume of gas produced (cm3) / 15 seconds = initial rate (cm3/s).I would also like to comment on the control variables of this experiment. This may seem a nice old 'rates of reaction' design but I would like to emphasise that you are using a catalyst. Thus any variables which may affect the productivity of a catalyst (apart from temperature which is your independent variable) must be controlled. These include, heavy metal volume and concentration, volume and concentration of inhibitors, pH of the solution, and the obvious things like volume and concentration of catalyst and hydrogenperoxide.Hope this helped.Thank you sooo much, it really helped me a lot! Thanks for the advise as well, Ill definitely keep it in mind while writing it:DD Reply Link to post Share on other sites More sharing options...
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