AQA AS Specimen Paper 2 Q2

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Figure 1 shows apparatus used in an experiment to determine the enthalpy of combustion of leaf alcohol. Figure 1 50.0 g sample of water The alcohol is placed in a spirit burner and weighed. The burner is lit and the alcohol allowed to burn for a few minutes. The flame is extinguished and the burner is re-weighed. The temperature of the water is recorded before and after heating. Table 1 shows the results obtained. Table 1 Initial mass of spirit burner and alcohol / g Final mass of spirit burner and alcohol / g Initial temperature of water / C Final temperature of water / C 56.38 55.84 20.7 40.8 0 2 . 1 Write an equation for the complete combustion of leaf alcohol (CH3CH2CH=CHCH2CH2OH). [1 mark] Barcode Typesetter code<br /> Enthalpy of combustion = Units = 0 2 . 2 0 2 . 3 Barcode Use the results from Table 1 to calculate a value for the enthalpy of combustion of leaf alcohol. Give units in your answer. (The specific heat capacity of water is 4.18 J K1 g1) [4 marks] State how your answer to Question 2.2 is likely to differ from the value quoted in reference sources. Give one reason for your answer. [2 marks] Question 2 continues on the next page Typesetter code Turn over <br /> 0 2 . 4 A 50.0 g sample of water was used in this experiment. Explain how you could measure out this mass of water without using a balance. [2 marks] Barcode Typesetter code<br />

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