• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

This is decomposition reaction because the H O is breaking down to simpler H O + O H O forms in cells this is toxic and must be removed rapidly. Catalyse catalyses the breakdown in cells. Potato cells contain catalyse enzymes.

Extracts from this document...


INTRODUCTION I am investigating how surface area affects the rate of oxygen production when a potato is placed in a solution of hydrogen peroxide. This experiment between hydrogen peroxide and the potato which contains an enzyme which is a catalyst will allow me to clearly see the effects to rate of oxygen production as surface area is changed. Reaction 2H O O + 2H O From previous work and my scientific knowledge I know these factors affect rate of oxygen production: 1) Surface area (the factor I investigated) 2) Temperature 3) Concentration Investigating how surface area affects oxygen production because I felt it would give the clearest answer on how rate of oxygen production is affected by surface area, also from previous knowledge I believe the results will give me wider scope for analysis and evaluation. I chose to use a range of surface areas between 2 ends of cylinder and 64 ends from the potato cylinder. This range will allow me to get a wide spread of results and allow me to see any changes clearly and get a deep understanding of how oxygen production is affected. These are the steps I took to make sure that all conditions fair and to keep all variables constant also to insure the results were clear and correct. ...read more.


The diameter of the potato cylinders is about 6mm. Then lay all the cylinders and cut them to the same length, the length of the shortest cylinder. The length should be no smaller then 40mm. Now 2 cylinders are cut in half to give two pieces, 2 cylinders are cut into 4 equal pieces; another 2 are cut into 8 equal pieces. Another 2 are cut into 16 pieces with another 2 into 32 pieces, 2 are left uncut. A scalpel is used to cut the potato cylinders. To make sure all pieces are equal measure with ruler. Measure 4cm of hydrogen peroxide accurately into the graduated test tube. After this is completed the stopwatch is checked to see if the timer is reset. Once this is done and the equipment is in place it is ready for the experiment. The potato cylinder is put into the acid and the timer is started, every 15 seconds the amount of oxygen produced is measured using the graduated test tube and is recorded. This is done for two minutes every 15 seconds then the timer is stopped and all results are recorded. Once the experiment is completed and the graduated test tube is washed and dried and the experiment is repeated for each different surface area twice. ...read more.


Error of graph plots = 0.5 x 10 -2 X 100 =12.5% 4.0 x 10 -2 Accuracy of Graph = diff X (1000) Avg. value PROCEDURAL ERRORS ==> Reaction time of hand-eye - error of 0.1s (automatic timer by laser) ==> Not all the bits of potato are in the acid when timer is started - error 5% (automatic stirrer) ==> The potato may have lost some of the catalyse (Use newly grown potato) ==> Judging accurately the amount of O produced. (automatic detector) ==> Temperature not always being the same (measure and control temperature) INSTRUMENTAL ERRORS ==> Measuring cylinder 7cm error in 0.5cm - 2% error ==> Length of potato (4cm) error of 1mm - 2.5% error (metal ruler) ==> Time over 10s error 0.1 - 1% error (automatic) ==> Temperature 2 C, error due to it being not being able to be kept constant 5% ==> Whether equipment is washed and dried properly - 2% Total percentage of maximum possible errors is 17.5% OTHER EXPERIMENTS ==> More results at each surface area - to get a better average ==> Use higher and lower lengths of potato see effect on rate. ==> Use higher and lower concentrations (such as 0.1, 2.2, 5) - to see how concentration affects rate of oxygen production ==> Use other enzymes such as lipase and protease ==> More and less amount of acid ==> At different temperatures ==> Using catalysts ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Life Processes & Cells essays

  1. Marked by a teacher

    Investigating the breakdown of hydrogen peroxide by the enzyme catalyse in potatoes.

    4 star(s)

    Control Variables In this investigation, the variables that affect the activity of the enzyme, Catalase, were considered and controlled so that they would not disrupt the success of the experiment. During the experiment we kept a number of things constant to make it fair such as the substrate concentration.

  2. Free essay

    This experiment examines how the concentration of hydrogen peroxide affects the rates of reaction ...

    the way * I will were protective gloves in case of spillages * I will wear protective goggles to keep my eyes safe from the chemicals Method * First I collected my equipment * Next I put on some gloves and safety goggles to protect my hands and eyes from

  1. Hypothesis: Increasing the surface area of the potato cylinders will increase the number of ...

    Substrate concentration - The following graph shows the effect of substrate concentration on the rate of reaction. Rate of reaction Substrate concentration From observing the graph it is clear that as the substrate concentration increases so does the rate of reaction (but only if the enzyme concentration is kept constant).

  2. The Decomposition of hydrogen peroxide by catalyse

    From there it will go in the conical flask along with 50mls of hydrogen peroxide. I will quickly put on the cork with a delivery tube on it, on the flask, place the u-bend of the tube into the measuring cylinder and time a minute on the stopwatch.

  1. Investigating the breakdown of hydrogen peroxide by catalyse.

    prediction I predict that if i increase the amount of potato I use, the amount of oxygen produced will Increase, because I think if you increase/ double one of the variables then it will increase/double the out come variable. In this experiment the potato speeds up the reaction of hydrogen peroxide producing oxygen.

  2. Investigating the Effect of Catalyse on Hydrogen Peroxide.

    of Reaction = Average O2 produced / 60 seconds (*100 if plotting a graph to get easier figures) The first graph shows the amount of oxygen produced against the temperature of the reaction. It shows that the enzymes inside potatoes have an optimum temperature of about 38�C.

  1. The Decomposition of Hydrogen Peroxide.

    The hotter the temperature gets after this the less enzymes there will be still working and so the rate of the reaction will decrease rapidly. I know that the rate oxygen is produced is directly proportional to the rate of the reaction so I can therfore predict that oxygen will

  2. An investigation into how enzyme concentration (catalyse in a potato) affects the rate of ...

    Therefore the larger the surface area exposed, the faster the reaction rate. Ph Level The majority of enzymes work most effectively at Ph 7. Substrate molecules fit into the enzyme's active site because of the surface electrical charge of amino acids in the enzyme molecule and the charge of the substrate molecule.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work