Answer ALL questions. 01. The three states of matter are solid, liquid and gas. The diagram shows how the particles are arranged in each of these states. (a) Use words from the box to show the changes of state labelled X, Y and Z. You may use each word once, more than once or not at all. (3) X Y Z (b) Which statement best describes the movement of the particles in a gas? A B C D The particles vibrate about fixed positions. The particles slide past one another. The particles move freely. The particles do not move at all. (Total for Question = 4 marks) 2
02. The element carbon has three common isotopes. These are carbon-12, carbon-13 and carbon-14. (a) Complete the table to show the number of protons and neutrons in each isotope of carbon. (b) Explain, in terms of electrons, why the three isotopes have the same chemical properties. (c) (i) State what is meant by the term relative atomic mass, A r (ii) A sample of carbon contained 98.90% carbon-12 and 1.10% carbon-13. Use this information to calculate the relative atomic mass of carbon in the sample. Give your answer to two decimal places. (3) Relative atomic mass... (Total for Question = 8 marks) 3
03. Like other metals, iron is malleable and is a good conductor of electricity. (a) (i) Explain why iron is malleable. (ii) Explain why iron is a good conductor of electricity. (b) Iron forms two sulfates. One has the formula FeSO 4 and the other has the formula Fe 2 (SO 4 ) 3 The addition of sodium hydroxide solution can be used to distinguish between solutions of these sulfates. (i) State what would be observed in each case. FeSO 4 Fe 2 (SO 4 ) 3 (ii) Write a chemical equation for the reaction of iron(ii) sulfate (FeSO 4 ) with sodium hydroxide solution. 4 (Total for Question = 8 marks)
04. This apparatus can be used to investigate the reduction of metal oxides. The mass of the metal oxide is measured before and after heating it in hydrogen. The results can be used to determine the formula of the oxide. (a) The hydrogen gas burns as it leaves the tube. (i) What substance is formed when hydrogen burns in air? (ii) Why is it important to relight the flame if it goes out? (b) These are the results for one experiment. Mass of solid before heating = 4.2 g Mass of solid after heating = 3.4 g These results may not be sufficient to find the mass of metal for use in determining the formula of the metal oxide. What further practical steps should be taken to confirm that an accurate value for the mass of metal has been obtained? 5
(c) In an experiment using a different metal oxide, a mass of 2.8 g of metal is obtained from 3.6 g of the metal oxide. (i) Calculate the mass of oxygen in the sample of the metal oxide. mass of oxygen =... g (ii) Calculate the amount, in moles, of oxygen atoms in the sample of the metal oxide. amount of oxygen =... mol (iii) The formula of the metal oxide is MO, where M is the symbol of the metal. Deduce the amount, in moles, of M in the sample of the metal oxide. amount of M =... mol (iv) What is the relative atomic mass of M? relative atomic mass of M =... 6 (Total for question = 10 marks)
05. A student used this apparatus to make and collect a sample of gas B. (a) The reaction in the flask can be shown by this word equation. metal + acid salt + gas B (i) The name of the salt formed in the student's experiment is A zinc sulfate B C D zinc sulfide zinc sulfite zinc sulfur (ii) The student could have used other metals in this experiment. Place crosses ( ) in two boxes to show the names of two other metals that could be safely used to make hydrogen. A copper B C D E iron magnesium potassium silver (b) Give one use of hydrogen. 7
(c) Water is formed when hydrogen combines with oxygen. Balance the equation for this reaction.... H 2 +... O 2... H 2 O (d) Equation 1 represents a reaction using cobalt(ii) chloride that can be used to show a liquid contains water. Equation 1 CoCl 2.2H 2 O(s) + 4H 2 O(l) CoCl 2.6H 2 O(s) In this reaction there is a colour change from blue to pink. (i) Which word describes both cobalt compounds in equation 1? A anhydrous B C D aqueous hydrated saturated (ii) When the product in equation 1 is gently heated, another reaction occurs. Equation 2 represents this reaction. Equation 2 CoCl 2.6H 2 O(s) CoCl 2.2H 2 O(s) + 4H 2 O(g) What do equations 1 and 2 suggest about the reactions? 8 (Total for Question = 7 marks)
06. The diagrams show the reactions of some metals with cold water and with dilute hydrochloric acid. (a) Answer the following questions, using only the metals that appear in the diagrams. (i) Name two metals that react with cold water.... and... (ii) Name one metal that reacts with dilute hydrochloric acid but not with cold water. (iii) Arrange the five metals in order of reactivity. Most reactive metal... (3)......... Least reactive metal... (b) Some magnesium powder is added to dilute sulfuric acid in a test tube. A colourless solution is formed and a gas is given off. When more magnesium is added, the reaction continues for a while and then stops, leaving some magnesium powder in the test tube. When a flame is placed at the mouth of the test tube, the gas burns with a squeaky pop. (i) Identify the gas produced. 9
(ii) Suggest why the reaction stops. (iii) State the name of the colourless solution. (iv) How could you separate the magnesium powder from the colourless solution? (c) In some fireworks, magnesium powder reacts quickly with oxygen in the air. During this reaction heat energy is produced. (i) What name is given to reactions in which heat energy is produced? (ii) Name the compound formed when magnesium reacts with oxygen. (Total for Question = 12 marks) 10
07. A group of students investigated the reaction between marble chips (calcium carbonate) and dilute hydrochloric acid. The equation for this reaction is CaCO 3 (s) + 2HCl(aq) CaCl 2 (aq) + H 2 O(l) + CO 2 (g) They wanted to find the effect of changing the concentration of hydrochloric acid on the rate of reaction. The teacher provided a solution that she had labelled 100% hydrochloric acid. The teacher told them to do all their experiments using different concentrations of hydrochloric acid made by diluting the 100% hydrochloric acid by timing how long it took to collect carbon dioxide at room temperaturethe students used this apparatus. (a) The students tried to keep the amount of calcium carbonate constant by using the same number of marble chips in each experiment. State two other properties of the marble chips that should be the same in each experiment. 1 2 11
(b) The table shows how some of the students wrote down their results. The teacher said that she could only use the results from student 1 because the other students had not recorded enough information. Identify the piece of information that each student failed to record. (4) Student 2... Student 3... Student 4... Student 5... 12
(c) The students repeated the experiment to make sure that it was a fair test. They used a different supply of hydrochloric acid. They all measured the time to collect 100 cm 3 of carbon dioxide and calculated the rate of each reaction. Their results are shown in the table. (i) Plot these results on the grid and draw a straight line of best fit. (3) (ii) One of the points is anomalous. Circle this point on the graph. 13
(iii) Suggest two errors in the experiment that could have caused this anomalous result. 1.... 2.... (iv) Use your graph to estimate the rate of reaction using an acid concentration of 50%. Show on your graph how you obtained your answer. (Total for Question = 14 marks) 08. A student was asked to compare the industrial processes used to extract aluminium and iron from their ores. (a) (i) Name the main ore used as the source of iron. (ii) Aluminium is extracted from purified aluminium oxide. What is the formula of aluminium oxide? (iii) One solid element is used in the extraction of both metals. Identify this element and state its purpose in the extraction of aluminium. Element... Purpose... (iv) One gaseous element takes part in a reaction needed in the extraction of iron. Identify this element and state its purpose in the extraction of iron. Element... Purpose... 14
(b) The student wrote this statement: (i) What name is given to a reaction that involves both reduction and oxidation? (ii) Why does this equation represent a reduction reaction? Al 3+ + 3e Al (iii) The equation for a reaction that occurs in some extractions of iron is C + H 2 O CO + H 2 Identify the substance oxidised in this reaction, giving a reason for your choice. Substance oxidised... Reason... (c) Both extractions occur at a high temperature. Neither extraction uses a catalyst. (i) What is meant by the term catalyst? (ii) State one reason why cryolite is used in the extraction of aluminium. (d) Several equations can be written for the reactions occurring in the extractions. (i) Write the balanced chemical equation for the reaction between iron(iii) oxide (Fe 2 O 3 ) and carbon monoxide (CO). 15
(ii) This equation represents a reaction used to remove impurities in the extraction of iron. CaO + SiO 2 CaSiO 3 State the type of reaction occurring in this equation. (iii) Complete the table by giving the common name for calcium silicate. (Total for Question = 17 marks) 09. The table gives information about barium salts. (a) Complete the table by giving the formula of barium chloride and of barium carbonate. (b) The human stomach contains hydrochloric acid. Suggest why barium carbonate may cause poisoning when it enters the stomach. (c) Before patients have stomach X-rays they are given a sample of barium salt to swallow. Which salt in the table is safe to use? 16
(d) A student accidentally swallowed a small amount of barium hydroxide solution, which is poisonous. Suggest a reason why a solution of magnesium sulfate could be given to the student to swallow as a first aid treatment. Write the word equation for the reaction that takes place. (3) Reason....... Word equation... (e) The table gives information about the first five elements in Group 2 of the Periodic Table. Use the information in the table to help you answer the questions. (i) Suggest how barium reacts with cold water and with air. Reaction with cold water.. Reaction with air.. (ii) Use your answer to (e)(i) to suggest how barium should be stored. (iii) Suggest a connection between the atomic number and the reactivity of the elements in Group 2. 17 (Total for Question = 12 marks)
10. A student investigates how temperature affects the rate of reaction between two colourless solutions containing ions. When he mixes the solutions, a reaction takes place between the ions and after a while the mixture suddenly turns blue. He performs the experiment at five different temperatures and on each occasion he measures the time taken for the mixture to turn blue. The table shows his results. (a) (i) Plot the results on the grid and draw a curve of best fit. (3) 18
(ii) Use your graph to estimate the time taken for the mixture to turn blue at 50 C. (iii) What does the graph show about the relationship between temperature and time taken? (b) Explain, in terms of particles, why an increase in temperature increases the rate of this reaction. (3).................. (c) State a variable that must be kept constant for the experiment to be valid (a fair test). 19 (Total for Question = 9 marks)
11. This is a description of how the orange colouring can be extracted from rose petals. crush the petals using a pestle and mortar add the crushed petals to some ethanol in a beaker heat to about 60 C and stir to produce an orange solution separate the orange solution from the petals (a) (i) Suggest why ethanol is used instead of water. (ii) Ethanol is a flammable liquid. Suggest how it could be heated safely. (iii) How could the orange solution be separated from the petals? (b) The orange colouring is analysed using chromatography and is found to consist of two different colours, red and yellow. The diagram shows the chromatography paper at the start of the experiment. Complete the diagram to show a possible result at the end of the experiment. (Total for Question = 5 marks) 20
12. The diagram shows some pieces of apparatus used to measure volumes. A student was given a large bottle containing sodium hydroxide solution and a supply of dilute sulfuric acid of known concentration. He was allowed to use normal laboratory apparatus, including the pieces of apparatus shown in the diagram. He was told to plan an experiment to find the concentration of the sodium hydroxide solution. This is his plan. Step 1 Obtain about 150 cm 3 of each solution. Step 2 Use a measuring cylinder to add exactly 25.0 cm 3 of sodium hydroxide solution to a conical flask. Step 3 Add a few drops of universal indicator to the conical flask. Step 4 Use a burette to add the sulfuric acid to the conical flask until the indicator changes colour. (a) (i) Give the name of the most suitable piece of apparatus in the diagram that should be used in Step 1. (ii) Give the name of the piece of apparatus in the diagram that should be used instead of a measuring cylinder in Step 2. (iii) State why universal indicator is not a good choice for this experiment and suggest an indicator that would be more suitable. 21
(iv) Why is a pipette not suitable for adding the acid in Step 4? (b) The diagram shows the burette readings in one experiment before and after adding the acid. Use the readings to complete the table, entering all values to the nearest 0.05 cm 3. (3) (c) The student repeated the experiment using a different concentration of sodium hydroxide solution and recorded these results. The volumes of acid added during these titrations are not all the same. The average (mean) volume of acid should be calculated using only concordant results. Concordant results are those volumes that differ from each other by 0.20 cm 3 or less. 22
(i) Identify the concordant results by placing ticks ( ) in the table where appropriate. (ii) Use your ticked results to calculate the average (mean) volume of acid added. Average (mean) volume of acid =... cm 3 (d) The student used the same method to find the concentration of a solution of potassium hydroxide. The equation for the reaction is These are his results. 2KOH + H 2 SO 4 K 2 SO 4 + 2H 2 O He used these results to calculate the concentration of the potassium hydroxide solution. There is one mistake in each step of the calculation. What correction should the student make in each step? (i) Step 1... (ii) Step 2... (iii) Step 3. (Total for Question = 14 marks) 23 (Total for paper = 120 marks)