Rate of reaction Essay Example for Free

Rate of reaction Essay Apart from these few improvements I think the equipment and the method I used was an appropriate way of investigating how concentration effects the rate of reaction on an enzyme. A variable that I could try for an extra experiment is temperature. I could try increasing the temperature of the catalase to see if increasing the temperature has the same effect on an enzyme as it does with concentration. This would help me to see which variable, temperature or concentration has a greater effect on the volume of oxygen produced from the reaction of an enzyme. I am going to work out the rate of reaction from the average value of each of the concentrations of hydrogen peroxide. I will work out the rate of reaction for every 10 second from the average values by using my graphs. Reaction Rate for the concentration of   Reaction Rate for the concentration of 6%  cm3/s From looking at these calculations I can say that for all the concentrations of hydrogen peroxide the reaction rate was fastest at the start of the reaction. During the reaction the rate decreased and eventually the reaction stopped. I can explain this by using the lock and key model. This occurs because the catalase is breaking the particles of the hydrogen peroxide to form into oxygen. This causes the hydrogen peroxide to get used up as the catalyst can alter the rate of reaction without getting used up. This then leaves the catalase to react with no substance. Data Logging Data logging is another experiment I did to extend my experiment. I looked at the enzyme activity experiment in a different way. This time I used the same quantity of catalase and hydrogen peroxide but instead of measuring the volume of oxygen produced, I found out the temperature increase for each of the different concentrations of hydrogen peroxide. Method 1. Collect all equipment and set the experiment up 2. Wear safety glasses as you are using chemicals 3. Pour 25cm3 of each concentration of hydrogen peroxide into a measuring cylinder 4. Pour each concentration of hydrogen peroxide into three different polystyrene cups 5. Measure 1mm of catalase into three different syringes 6. Make sure that the end of the probe is touching the bottom of the cup and that the hydrogen peroxide is completely covering it 7. Inject all three of the catalase at the same time into each polystyrene cup 8. At the same time start the computer as you inject the catalase, to start of the measurement of the temperature, of the hydrogen peroxide 9. Watch how the computer measures the temperature for 2minutes as it transfers all the information into a graph 10. Stop the graph at 2 minutes and print out the results Conclusion From my results I can see that the 6% concentration of hydrogen peroxide has given of the highest temperature. This is because the concentration of 6% has many particles of hydrogen peroxide which will have a greater chance of colliding with the catalase. The concentration of 1. 5% and 3% has given of less heat causing a lower temperature. This is because they have less particles of hydrogen peroxide to collide with the enzymes. This result can be explained by the kinetic and collision theory. The increase in heat gave an increase in the kinetic energy. This means that there would be more collision between the hydrogen peroxide particles and the catalase, which would lead to a better chance of collision being successful. This experiment is related to my first experiment as the increase in concentration gave off more oxygen which gave us an increase in temperature. I found out that the 6% concentration gave of the most oxygen which causes a rise in temperature and the 1. 5% gave of the least oxygen causing a lower temperature. The 6% also gave off the most oxygen in the shortest time whereas the 1. 5% concentration gave off the least oxygen in the longest time. From looking at my graph I can see that the 6% concentration had the steepest slope which if I relate back to my rates of reaction theory. I can say that the steeper the slope the faster the reaction. The 1. 5% concentration had the smallest gradient which means it had the slowest rate of reaction. Overall this proves my original prediction, that the 6% concentration of hydrogen peroxide has the fastest rate of reaction and the 1. 5% concentration has the slowest. Reaction Rates During a reaction, reactants are being used up and products are forming. The reaction rate tells us how fast the reaction is taking place. You can calculate the reaction rate by measuring how much reactant is used up or how much product forms in a given time. Reaction rate = change in amount of a substance time taken The reaction rate can also be calculated by using a graph. The slope of the graph tells us how quickly the reaction is happening. The steeper the slope, the faster the reaction Results from the Trial Experiment Time (s) Volume of O2 evolved (cm3) 1. 5% Volume of O2 evolved (cm3) 3% Volume of O2 evolved (cm3) 6% Average I did a trial experiment to help me understand the experiment. The trial experiment showed me how quickly each concentration of hydrogen peroxide produced the amount of oxygen gas in one minute. I also learnt that slow pressure is needed with the small gas syringe because too much pressure causes the catalase to spill out. Results from the concentration of 1. 5% Time(s) oxygen evolved (cm3)oxygen evolved (cm3) oxygen evolved (cm3) oxygen evolved (cm3) oxygen evolved (cm3) oxygen evolved (cm3) average. I am going to use columns 5,6 and 7 for my average because these columns have the nearest results to each other and the range of results are realistic. Results from the concentration of 3% Time(s) oxygen evolved (cm3) oxygen evolved (cm3) oxygen evolved (cm3) oxygen evolved (cm3) oxygen evolved (cm3) average 1 I will be using columns 4,5 and 6 for my average because these columns have the nearest results to each other and the range of results are realistic. Results from the concentration of 6% Time(s) oxygen evolved (cm3) oxygen evolved (cm3) oxygen evolved (cm3) oxygen evolved (cm3) average. I will use column 2,3 and 4 for my average because these columns have the nearest results to each other and the range of results are realistic. Time (s) Temperature (oC) 1. 5% Temperature (oC) 3% Temperature Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.