Wednesday, July 31, 2019
Gcse Isa Chemistry Calorimetry
Hypothesis: I believe that alcoholic compounds with bigger relative formula mass will release more energy in combustion reaction than the less alcoholic hydrocarbons compounds. Equipment: Different types of alcohols in spirit burner (CH4, C2H6, C3H8, C4H10, C5H12), Thermometer, water, beaker, scale, measuring cylinder, tripods, clamp, gauze, heat mat, lighter or matches. Hazard: Most of alcohol we using are flammable, irritant, toxic and harmful. 1 provide spirit burners which have removable glass caps, this makes it easier and safer to extinguish the flames. à Make sure the wick fits tightly in the wick holder and that the wick holder fits tightly in the burner. 3 Fill and label spirit burners or dropper bottles with alcohols in advance of the experiment. Read this Practice Test Chem 105 Ensure any excess alcohol is wiped off the side of the burners. 5 careful considerations must be given on igniting the alcohols. The spirit burners must be kept upright when lighting. Do not tip onto the side. 6 make sure the alcohols are kept away from any source of heat. don't burn your self by touching any flames or hot water Method: 1- Fit the beaker inside the tripod, fill the beaker with 100ml of water after measuring it by the cylinder,à and take the initial temperature of water by using thermometer, 2- Measure the mass of theà first burner spirit (Methanol)à and record it, Put the spirit burner on the heat-mat under the beaker and ignite it 3- Keep stirring the water, when the temperature reach 50? Cà turn off the flame. 4- Reweigh the burner and workout the difference. ââ¬â Repeat the same steps 3 times and take the average of the alcohol used in burning. 6- Apply the same steps above with the all-different types of alcohol remaining to test (Ethanol, Propanol, B utanol, Pentanol) 7- Finally you need to work out theà energy released from each alcohol by applying this calculation à q = (specific heat capacity of water 4. 2) x mass of water(g) x ? t change in temperature(? C) Then divide the answer by the used alcohol to find out the released energy kJ/g Table: Energy transferred for alcoholAlcohol name| Test 1 (g)| Test 2 (g)| Test 3 (g)| Average (g) | Transferred energy (kJ/g)| Methane| | | | | | Ethane| | | | | | Propane| | | | | | Butane| | | | | | Pentane| | | | | | Make it fair test? The answer is the same as the control variables * Volume of water (100ml). * Temperature rise to 50? C. * Same starting temperature of the water. * Always weigh the alcohol burner without the lid. Independent variables: the type of alcohol Dependent variables: transferred energy from the combustion.
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