a i Describe as fully as you can the trends shown in the students results 3

A i describe as fully as you can the trends shown in

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1 (a) (i) Describe, as fully as you can, the trends shown in the students’ results.................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
(04) G/J92917/Jun13/CH2HP 1 (b) Sodium hydrogencarbonate is used as baking powder for making cakes. When the cake mixture is baked the sodium hydrogencarbonate decomposes. The equation for the reaction is: 2 NaHCO 3 (s) Heat Na 2 CO 3 (s) + H 2 O(g) + CO 2 (g) 1 (b) (i) The cake mixture rises when baked. Use the equation to suggest why. ............................................................................................................................................ ............................................................................................................................................ (1 mark) 1 (b) (ii) The same reaction can be reversed to produce sodium hydrogencarbonate from sodium carbonate. Na 2 CO 3 + H 2 O + CO 2 2 NaHCO 3 Do the reactants need to be heated? Give a reason for your answer. ............................................................................................................................................ ............................................................................................................................................ (1 mark)
5 Do not write outside the box (05) G/J92917/Jun13/CH2HP Turn over 1 (c) (i) Calculate the relative formula mass of sodium hydrogencarbonate (NaHCO 3 ). Relative atomic masses ( A r ): H=1; C=12; O=16; Na=23 ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ Relative formula mass ( M r ) = .................................................. (2 marks) 1 (c) (ii) Calculate the percentage by mass of carbon in sodium hydrogencarbonate. ............................................................................................................................................ ............................................................................................................................................ Percentage of carbon = .................................................. % (1 mark) ____ 9 Turn over for the next question
6 Do not write outside the box (06) G/J92917/Jun13/CH2HP 2 A student investigated the reaction between magnesium and hydrochloric acid. Hydrochloric acid Magnesium The equation for the reaction is: Mg(s) magnesium +2 HCl(aq) hydrochloric acid MgCl 2 (aq) magnesium chloride +H 2 (g) hydrogen 2 (a) Give two observations the student could make during the reaction. 1 ......................................................................................................................................... ............................................................................................................................................ 2 ......................................................................................................................................... ............................................................................................................................................ (2 marks) 2 (b) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. The student investigated how the rate of this reaction changed when the concentration of hydrochloric acid was changed. Write a plan the student could use. In your plan you should: describe how you would carry out the investigation and make it a fair test describe the measurements you would make. ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................
7 Do not write outside the box (07) G/J92917/Jun13/CH2HP Turn over ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ ............................................................................................................................................ (6 marks) ____ 8
8 Do not write outside the box (08) G/J92917/Jun13/CH2HP 3 Ammonia is produced from nitrogen and hydrogen.

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• Spring '16
• nour
• Biology, RNA, Pastpaperquestions AQA Science, ........., Sodium chloride, Potassium Chloride