2 Answer all questions in the spaces provided. 1 The diagrams show the sub-atomic particles in four different atoms. Atom A Atom B Atom C Atom D Use the Chemistry Data Sheet to help you to answer these questions. 1 (a) Draw a ring around the correct answer to complete each sentence. energy level. 1 (a) (i) The centre of each atom is called the molecule. nucleus. bonds. 1 (a) (ii) The centre of each atom contains neutrons and electrons. protons. 1 (b) Complete the sentence. There is no overall electrical charge on each atom because the number of... is equal to the number of.... (02) G/K84795/Jun12/CH1FP
3 1 (c) What is the name of the element represented by atom D?... 1 (d) Which two of the atoms, A, B, C and D, are in the same group of the periodic table? Give a reason for your answer. Atom and atom Reason... (2 marks) 6 Turn over for the next question Turn over (03) G/K84795/Jun12/CH1FP
2 Answer all questions in the spaces provided. 1 The picture shows a diamond ring. Diamond Gold ring 1 (a) Diamond is a form of carbon. A carbon atom has six electrons. Draw the electronic structure of a carbon atom. Nucleus 1 (b) A gold atom has an atomic number of 79 and a mass number of 197. Complete the table to show the name and number of each sub-atomic particle in this gold atom. Name Number Proton 79 Electron......... (3 marks) (02) G/J80862/Jan12/CH1HP
3 1 (c) The bar chart shows the composition of this gold ring. 100 80 Percentage (%) of metal in the ring 60 40 20 0 Gold Silver Copper 1 (c) (i) Give the percentage of the other two metals in this gold ring. Silver is... % and copper is... % 1 (c) (ii) This gold ring is not made from 100 % gold. Give two reasons why. 1... 2... (2 marks) 7 Turn over (03) G/J80862/Jan12/CH1HP
12 7. A laboratory technician prepared a solution of sodium hydroxide, NaOH, in the following way. Examiner only He weighed out accurately 2.0 g of sodium hydroxide. He dissolved the sodium hydroxide in 250 cm 3 of water. The relative formula mass (M r ) of sodium hydroxide is 40. (a) Use this information to calculate the concentration of this sodium hydroxide solution in mol/dm 3. [2] Concentration of sodium hydroxide solution =... mol / dm 3 (b) A student was asked to carry out a titration to check the concentration of the sodium hydroxide solution. She carried out the titration using the apparatus shown below. 0.2 mol / dm 3 hydrochloric acid 25 cm 3 of sodium hydroxide solution and indicator WJEC CBAC Ltd. (4493-02)
13 The equation for the reaction taking place is as follows. Examiner only NaOH + HCI NaCl + H 2 O The titration was carried out three times and the results obtained are shown below. Titration 1 2 3 Volume of hydrochloric acid added (cm 3 ) 22.2 22.7 22.6 Calculate the number of moles of hydrochloric acid that reacted and hence the concentration of the sodium hydroxide solution. [4] Concentration of sodium hydroxide solution =... mol / dm 3 6 WJEC CBAC Ltd. (4493-02) Turn over.
14 8. Describe the similarities in the reactions of ethanoic acid and sulfuric acid with metals, carbonates and bases. Describe and explain any differences observed. You should include relevant equations in your answer. [6 QWC] Examiner only END OF PAPER 6 WJEC CBAC Ltd. (4493-02)
14 6 Icing on cakes is tested to check that safe colours were used when they were made. Paper chromatography is one method of testing which colours are in cake icing. 6 (a) The diagram shows an experiment a student did. Lid Container Chromatography paper Start line Solvent Safe food colours Colouring from cake icing 6 (a) (i) Suggest why there is a lid on the container. 6 (a) (ii) The start line should be drawn in pencil not in ink. Suggest why. (14)
15 6 (b) The diagram shows the results of the paper chromatography experiment. Safe food colours Colouring from cake icing 6 (b) (i) How many different food colours were used in the colouring from the cake icing? 6 (b) (ii) Is the cake icing safe to eat? Give a reason for your answer.... Question 6 continues on the next page Turn over (15)
12 5 Read the information. Graphene Scientists have made a new substance called graphene. The bonding and structure of graphene are similar to graphite. Graphene is made of a single layer of the same atoms as graphite. Graphene Graphite Use the information above and your knowledge of graphite to answer the questions. 5 (a) This part of the question is about graphene. Choose the correct answer to complete each sentence. 5 (a) (i) ionic covalent metallic The bonds between the atoms in graphene are.... 5 (a) (ii) chromium carbon chlorine Graphene is made of... atoms. 5 (a) (iii) 2 3 4 In graphene each atom bonds to... other atoms. (12)
13 5 (b) This part of the question is about graphite. Graphite is used in pencils. Explain why. Use the diagrams to help you. (2 marks) 5 Turn over for the next question Turn over (13)
10 4 The diagram represents an electrolysis cell for extracting aluminium. The current will only flow when the electrolyte is molten. Molten electrolyte containing aluminium oxide O 2 O 2 O 2 Al 3+ Al 3+ Oxygen forms at the positive electrode Aluminium forms at the negative electrode 4 (a) The electrolyte is aluminium oxide mixed with another substance. 4 (a) (i) What is the name of the other substance in the electrolyte? Draw a ring around the correct answer. cryolite rock salt limestone 4 (a) (ii) Draw a ring around the correct answer to complete the sentence. condense the aluminium oxide. This other substance is added to lower the melting point of the aluminium oxide. 4 (b) (i) Oxide ions (O 2 ) move to the positive electrode. Explain why. raise the boiling point of the aluminium oxide. (2 marks) (10)
11 4 (b) (ii) Oxygen is formed at the positive electrode. The oxygen then forms carbon dioxide. The equation for the reaction is shown below. Complete the sentence. C + O 2 CO 2 The name of the element which reacts with oxygen is.... 4 (b) (iii) The positive electrode gets smaller. Suggest why. 4 (c) Aluminium is used in an alloy with magnesium to make drinks cans. The diagrams show the arrangement of atoms in pure aluminium and in the alloy. Pure aluminium Alloy The alloy is harder than pure aluminium. Explain why. Use the diagrams to help you. (2 marks) 8 Turn over (11)
17 7 (a) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. The salt called potassium chloride is made when potassium hydroxide solution reacts with hydrochloric acid. potassium hydroxide + hydrochloric acid potassium chloride + water solution solution Describe a method for making crystals of potassium chloride from potassium hydroxide solution and hydrochloric acid. In this method you should: describe how you will add the correct amount of the hydrochloric acid to neutralise the potassium hydroxide solution describe how you will get crystals of potassium chloride. (6 marks) Question 7 continues on the next page Turn over (17)
18 7 (b) Ammonium nitrate is another salt. Ammonium nitrate is made when ammonia solution is neutralised with an acid. Name the acid to complete the word equation. 7 (c) Read the information. ammonia +... acid ammonium nitrate Ammonium nitrate good or bad? Some farmers put a lot of ammonium nitrate on their farmland. Many people are worried about this use of ammonium nitrate. Rain water can wash the ammonium nitrate off the farmland and into rivers and lakes. The ammonium nitrate may get into drinking water supplies and could be harmful to health. 7 (c) (i) Why do some farmers put ammonium nitrate on their farmland? (18)
19 7 (c) (ii) Which one of the questions in the table cannot be answered by science alone? Tick ( ) one question. Question Tick ( ) How much ammonium nitrate is in drinking water? Should farmers stop using ammonium nitrate on their farmland? Is ammonium nitrate soluble in rain water? Give two reasons why this question cannot be answered by science alone. (3 marks) 11 END OF QUESTIONS (19)