SCIENCE course work b

Investigation Titles 2014 Biology Investigate and compare the effects of pH on the catalytic effect of the enzyme catalase , found in (a) celery and (b) animal liver, on the rate of breakdown of hydrogen peroxide. Chemistry Investigate and compare how the solubilities, in water, of (a) potassium chloride and (b) sodium carbonate (anhydrous) change with temperature. Physics Investigate and compare how the rates of flow of powdered or granulated solids through a funnel are affected by (a) the size of the solid particles and (b) any one of the funnel dimensions. 

http://www.nce-mstl.ie/_fileupload/Science%20resources/Biology%20resources/Class%20Activity-%20Enzymes%20in%20Action!.pdfTest Tube number:  1. 5 mL hydrogen peroxide + 1 ½ cm2 piece of liver  2. 5 mL of the hydrogen peroxide + 1 ½ cm2 piece of cooked liver  3. 5 mL hydrogen peroxide + a pinch of sand  4. 5 mL hydrogen peroxide + 1½cm2 piece of ground liver  5. ½ mL of the hydrogen peroxide and 1½cm2 piece of liver from test tube  Using Raw Liver as a Catalyst:    1. Get a 400-600 mL beaker and fill it about 2/3 full of water.  Get a test tube and fill it with water. Put your thumb on it, invert it and place it in the beaker of water so  it is ready to collect gas.    2. Set up the apparatus similar to the  following diagram: 3. Remove the stopper from the test tube on the left and add 5.0 mL of 3% Hydrogen Peroxide (H2O2) to  the test tube.  4. Obtain a small piece of raw liver, drop it in the test tube on the left and quickly put the stopper on again.  5. Get students to record the rate of reaction (i.e. timing the length of time it took for the bubbles to form)  6. When there is no more bubbling in the test tubes, get a glowing splint ready and remove the test tube  on the right. Quickly test the gas with the glowing splint.    Adding Cooked Liver to Hydrogen Peroxide    1. Refill the test tube on the right with water and invert it in the beaker of water so it is ready to collect  gas.  2. Remove the test tube on the left and clean it out. Add 5.0 mL of 3% Hydrogen Peroxide (H2O2) to it.  3. Obtain a small piece of raw liver and cook it over a bunsen burner flame until it is cooked well. (No need  to add barbeque sauce!)  4. Drop the piece of cooked liver in the test tube on the left and quickly put the stopper on again.  5. Get students to record the rate of reaction (i.e. timing the length of time it took for the bubbles to form)  6. When there is no more bubbling in the test tubes, take the equipment apart and clean everything out Extension:  Based on the materials available, get students to design an experiment to establish the reaction of  hydrogen peroxide in the absence of the catalase enzyme.  Students may suggest sand plus hydrogen peroxide or hydrogen peroxide alone in a test tube.  Ask student how they might investigate the effects of concentration on these reaction rates?  Students may suggest using more hydroxide and/or more liver in the test tube.  Students may suggest crushing the liver to expose more enzymes to the hydrogen peroxide.  Ask student how might they record their observations?  Students may suggest recording the time to reaction, or devise a system for recording the intensity of the  reaction.    To test these extension questions follow the same procedure as above, test the effect of the following on  reaction rate:  5 mL hydrogen peroxide + a pinch of sand  5 mL hydrogen peroxide + 1½cm2 piece of ground liver  ½ mL of the hydrogen peroxide and ½ the piece of liver from test tube  Get students to record the results.  Note: if you do not have access to the apparatus shown in the diagram above, this demonstration can be  conducted in two test tubes, one with 5 mL hydrogen peroxide + 1 ½ cm2 piece of liver and the other  with 5 mL of the hydrogen peroxide + 1 ½ cm2 piece of cooked liver. The test tube with the raw liver will  produce oxygen gas which can be tested with a glowing splint and the test tube with the cooked liver  will not relight a glowing splint as no oxygen will be produced

TeacherExpt:Catalysts for the decomposition of hydrogen peroxide This procedure is designed as a demonstration to be performed by a teacher or other qualified person.Several measuring cylinders are set up each containing a little washing up liquid and a small amount of a catalyst for the decomposition ofhydrogen peroxide. Hydrogen peroxide is poured into the cylinders and a foam rises up the cylinders at a rate that depends on the effectiveness of the catalyst. Contents  [hide] 1 Apparatus and chemicals 2 Technical notes 3 Procedure 3.1 Health & Safety 3.2 Procedure 3.3 Before the demonstration 3.4 The demonstration 4 Teaching notes 4.1 Theory 4.2 Extensions 5 Reference Apparatus and chemicals The chemical quantities given are for one demonstration. Safety goggles and nitrile gloves must be worn by the demonstrator Several 250 cm3 measuring cylinders – one for each catalyst to be used. A large tray to catch any foam that spills over the top of the cylinders. Stopwatch or clock with second hand. 75 cm3 of 100 volume hydrogen peroxide solution (Harmful at this concentration) About 0.5 g of powdered manganese(IV) oxide (manganese dioxide, MnO2) (Harmful) About 0.5 g of lead(IV) oxide (lead dioxide, PbO2) (Toxic and dangerous for the environment) About 0.5 g of iron(III) oxide (red iron oxide, Fe2O3) (Low hazard) A small piece (about 1 cm3) of potato. A small piece (about 1 cm3) of liver. Technical notes 75 cm3 of 100 volume hydrogen peroxide solution (Harmful at this concentration) Refer to CLEAPSS® Hazcard 50About 0.5 g of powdered manganese(IV) oxide (manganese dioxide, MnO2) (Harmful at this concentration) Refer to CLEAPSS® Hazcard 60About 0.5 g of lead(IV) oxide (lead dioxide, PbO2) (Toxic and dangerous for the environment) Refer to CLEAPSS® Hazcard 56About 0.5 g of iron(III) oxide (red iron oxide, Fe2O3) (Low hazard). Refer to CLEAPSS® Hazcard 55A Used liver should be wrapped up in paper and placed in the dustbin. The use of the washing up liquid helps prevent the catalyst from going into the atmosphere but there may be some hydrogen peroxide aerosol. To dispose of the lead(IV) oxide, filter it off from the solution, wash it and let it dry. It could be reused. Procedure Health & Safety The demonstrator should wear goggles and nitrile gloves (see CLEAPSS® Hazcard 50) Procedure Before the demonstration A. Line up five 250 cm3 measuring cylinders in a tray. Add 75 cm3 of water to the 75 cm3 of 100 volume hydrogen peroxide solution to make 150 cm3 of 50 volume solution. The demonstration A. Place about 1 cm3 of washing up liquid into each of the measuring cylinders. To each one add the amount of catalyst specified above. Then add 25 cm3 of 50 volume hydrogen peroxide solution to each cylinder. The addition of the catalyst to each cylinder should be done as nearly simultaneously as possible – using two assistants will help. Start timing. Foam will rise up the cylinders. The lead dioxide will probably be fastest, followed by manganese dioxide and liver. Potato will be much slower and the iron oxide will barely produce any foam. This order could be affected by the surface areas of the powders. Time how long each foam takes to rise to the top (or other marked point) of the cylinder. The foam from the first three cylinders will probably overflow considerably.B. Place a glowing spill in the foam; it will re-light confirming that the gas produced is oxygen. Teaching notes Some students may believe that the catalysts – especially the oxides – are reactants because hydrogen peroxide is not noticeably decomposing at room temperature. The teacher could point out the venting cap on the peroxide bottle as an indication of continuous slow decomposition. Alternatively s/he could heat a little hydrogen peroxide in a conical flask with a bung and delivery tube, collect the gas over water in a test-tube and test it with a glowing spill to confirm that it is oxygen. This shows that no other reactant is needed to decompose hydrogen peroxide.NB: Simply heating 50 volume hydrogen peroxide in a test-tube will not succeed in demonstrating that oxygen is produced. The steam produced will tend to put out a glowing spill. Collecting the gas over water has the effect of condensing the steam. It is also possible to ‘cheat’ by dusting a beaker with a tiny, almost imperceptible, amount of manganese dioxide prior to the demonstration and pouring hydrogen peroxide into it. Bubbles of oxygen will be formed in the beaker. Theory The reaction is : 2H2O2(aq) → 2H2O(l) + O2(g)This is catalysed by a variety of transition metal compounds and also by peroxidase enzymes found in many living things. Extensions Repeat the experiment but heat the liver and the potato pieces for about five minutes in boiling water before use. There will be almost no catalytic effect, confirming that the catalyst in these cases is an enzyme that is denatured by heat.Investigate the effect of using lumpy or powdered manganese dioxide. The powdered oxide will be more effective because of its greater surface area.Try using other metal oxides or iron filings as catalysts.Animal blood may be used instead of liver if local regulations allow this.One teacher suggested measuring the height of the foam over suitable time intervals and plotting a graph. Reference This experiment has been adapted from Classic Chemistry Demonstrations, Royal Society of Chemistry, London, p.145-146 http://www.rsc.org/learn-chemistry/wiki/TeacherExpt:Catalysts_for_the_decomposition_of_hydrogen_pero...

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