Half Term Paper 2 Yr Chemistry Foundation Name: Class: Date: Time: 80 minutes Marks: 78 marks Comments: Multiple choice questions: Page
Q.A student investigated the rate of reaction between marble chips and hydrochloric acid. Figure shows the apparatus the student used. Figure (a) What is A? Tick one box. cotton wool limestone poly(ethene) rubber bung Table shows the student s results for one investigation. On Figure 2: Plot these results on the grid. Draw a line of best fit. Figure 2 Page 2
(3) (c) Use Figure 2 to complete Table 2. Table 2 Mass lost after 0.5 minutes Time taken to complete the reaction... g... s (2) (d) The equation for the reaction is: 2HCl(aq) + CaCO3(s) CaCl2(aq) + H2O(l) + CO2(g) Explain why there is a loss in mass in this investigation.......... (2) (e) Another student investigated the rate of a different reaction. Table 3 shows the results from the different reaction. Table 3 Mass lost when the reaction was complete Time taken to complete the reaction 9.85 g 2 minutes 30 seconds Calculate the mean rate of the reaction using Table 3 and the equation: mean rate of reaction = Give your answer to two decimal places.... Mean rate of reaction =... g / s (2) (f) The student measured the change in mass of the reactants. Describe another method, other than measuring the change in mass of the reactions, that the student could have used to find the rate of the reaction between marble chips and hydrochloric acid.......(2) (g) Another student planned to investigate the effect of temperature on the rate of reaction. The student predicted that the rate of reaction would increase as the temperature was increased. Give two reasons why the student s prediction is correct. Tick two boxes. Page 3
The particles are more concentrated. The particles have a greater mass. The particles have a larger surface area. The particles have more energy. The particles move faster. Q2.A student investigated the rate of reaction between sodium thiosulfate solution and dilute hydrochloric acid, as shown in Figure. (2) (Total 4 marks) The reaction produced a precipitate, which made the mixture turn cloudy. The student timed how long it took until she could no longer see the cross. She calculated the rate of the reaction. (a) The equation for the reaction is: Na2S2O3(aq) + 2 HCl(aq) 2 NaCl(aq) + S(s) + SO2(g) + H2O(l) Name the product that made the mixture go cloudy. The student investigated the effect of changing the temperature of the sodium thiosulfate solution on the rate of reaction. She plotted her results on a graph, as shown in Figure 2. Page 4
Describe the trends shown in the student s results....... (2) (c) The student then investigated the effect of changing the concentration of sodium thiosulfate solution on the rate of the reaction. (i) Suggest two variables the student would need to control to make sure that her results were valid....... (2) From this investigation the student correctly concluded: As the concentration of sodium thiosulfate solution doubles, the rate of reaction doubles. Explain the student s conclusion in terms of particles................ (3) (Total 8 marks) Page 5
Q3.Alkanes are hydrocarbons found in crude oil. (a) (i) Complete the sentence. Hydrocarbons contain the elements... and... only. Ethane is an alkane with the formula C2H6 Draw a ring around the correct answer to complete the sentence. CnHn Alkanes are hydrocarbons with the general formula CnH2n CnH2n+2 Crude oil is separated into useful fractions by fractional distillation. Describe and explain how crude oil is separated into fractions by fractional distillation. Use the diagram to help you answer the question................ (4) (c) Dodecane (C2H26) from crude oil is cracked to produce ethene (C2H4). (i) Complete the equation for this reaction. C2H26 2 C2H4 +... Give two conditions needed for cracking.... 2...(2) (Total 9 marks) Q4.This question is about hydrocarbons. (a) Most of the hydrocarbons in crude oil are alkanes. Page 6
(i) Large alkane molecules can be cracked to produce more useful molecules. The equation shows the cracking of dodecane. Give two conditions used to crack large alkane molecules.... 2... (2) The products hexene and ethene are alkenes. Complete the sentence. When alkenes react with bromine water the colour changes from orange to.... (iii) Butane (C4H0) is an alkane. Complete the displayed structure of butane. A group of students investigated the energy released by the combustion of four hydrocarbon fuels. The diagram below shows the apparatus used. Each hydrocarbon fuel was burned for two minutes. Table shows the students results. Table After two minutes Name and formula of hydrocarbon fuel Mass of fuel used in g Temperature increase of water in C Energy released by fuel in kj Energy released by.0 g of fuel in kj Relative amount of smoke in the flame Hexane, C6H4 0.8 40 6.80 20.74 very little smoke Octane, C8H8.0 54 22.68 20.62 some smoke Decane, C0H22.20 58 24.36 smoky Dodecane, C2H26.4 67 28.4 9.96 Page 7 very smoky
(i) Calculate the energy released by.0 g of decane in kj. Energy released =... kj (2) Suggest one improvement to the apparatus, or the use of the apparatus, that would make the temperature increase of the water for each fuel more accurate. Give a reason why this is an improvement....(2) (iii) The students noticed that the bottom of the beaker became covered in a black substance when burning these fuels. Name this black substance. Suggest why it is produced....(2) (iv) A student concluded that hexane is the best of the four fuels. Give two reasons why the results in Table 2 support this conclusion.... 2...... (2) (c) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Most car engines use petrol as a fuel. Petrol is produced from the fractional distillation of crude oil. Crude oil is a mixture of hydrocarbons. Sulfur is an impurity in crude oil. Car engines could be developed to burn hydrogen as a fuel. Hydrogen is produced from natural gas. Natural gas is mainly methane. Page 8
Table 2 shows information about petrol and hydrogen. Table 2 State of fuel at room temperature Word equation for combustion of the fuel Petrol Liquid petrol + oxygen carbon dioxide + water Hydrogen Gas hydrogen + oxygen water Energy released from combustion of g of the fuel 47 kj 42 kj Describe the advantages and disadvantages of using hydrogen instead of petrol in car engines. Use the information given and your knowledge and understanding to answer this question.... (6) (Total 8 marks) Q5.Crude oil is used to make useful substances such as alkenes and plastics. (a) The alkene shown is ethene. (i) Tick ( ) the correct formula for ethene. Formula Tick ( ) CH4 C2H4 C2H6 Page 9
Tick ( ) the name of the plastic formed when many ethene molecules join together. Name of plastic Tick ( ) Poly(ethene) Poly(ethenol) Poly(propene) Read the article about plastics and then answer the questions. THE PROBLEM WITH PLASTIC WASTE Millions of tonnes of plastics are made from crude oil every year. Most of the litter found on beaches is plastic waste. 80 % of plastics produced end up in landfill sites. (i) Draw a ring around the correct answer in the box to complete the sentence. decomposes. Plastic waste needs to be removed from beaches because it is reactive. is not biodegradable. Suggest a problem caused by 80 % of plastics going to landfill sites....... (iii) Suggest one way of reducing the amount of plastics going to landfill sites. Q6. Read the article.......(total 5 marks) Problem food colourings Scientists say they have evidence that some food colourings cause hyperactive behaviour in young children. These food colourings are added to some sweets. Page 0
W, X, Y and Z are food colourings that may cause hyperactive behaviour in young children. A scientist used chromatography to see if these food colourings were used in two sweets, S and P. The results are shown on the chromatogram. (a) Food colourings, such as W, X, Y and Z, are added to some sweets. Suggest one reason why....... In chromatography, the Rf value = Use the scale on the chromatogram to help you to answer this question. Which food colouring, W, X, Y or Z, has an Rf value of 0.7?... (c) From the chromatogram, what conclusions can the scientist make about the colourings in sweets S and P?............ Page
...... (3) (Total 5 marks) Q7.This question is about mixtures and analysis. (a) Which two substances are mixtures? Tick two boxes. Air Carbon dioxide Graphite Sodium Chloride Steel (2) Draw one line from each context to the correct meaning. Context Meaning A substance that has had nothing added to it Pure substance in chemistry A single element or a single compound A substance containing only atoms which have different numbers of protons Pure substance in everyday life A substance that can be separated by filtration A useful product made by mixing substances (2) Page 2
(c) What is the test for chlorine gas? Tick one box. A glowing splint relights A lighted splint gives a pop Damp litmus paper turns white Limewater turns milky (d) A student tested a metal chloride solution with sodium hydroxide solution. A brown precipitate formed. What was the metal ion in the metal chloride solution? Tick one box. Calcium Copper(II) Iron(II) Iron(III) (Total 6 marks) Q8.This question is about chemical tests. (a) Solutions of copper(ii) ions and iron(iii) ions produce coloured precipitates with sodium hydroxide solution. Draw one line from each metal ion to the colour of the precipitate it produces. Page 3
(2) Sodium hydroxide solution was added to a solution containing ions of a metal. A white precipitate was produced. The white precipitate dissolved in excess sodium hydroxide solution. Use the correct answer from the box to complete the sentence. aluminium magnesium potassium The ions in the solution were ions of.... (c) Low sodium salt contains sodium chloride and potassium chloride. A student used a flame test on low sodium salt. (i) What is the colour produced by sodium ions in a flame test?... What is the colour produced by potassium ions in a flame test?... (iii) Why is it not possible to tell from the flame test that both ions are present in low sodium salt?...... (Total 6 marks) Page 4
Q9.Figure shows how ethanol is made from plants and from crude oil. (a) What is the name of the reaction to produce ethanol from sugar? Tick ( ) one box. fermentation polymerisation reduction A student made ethanol from sugar. Figure 2 shows the apparatus used. (i) What change is seen in the limewater? Give a reason for your answer. (2) Page 5
The student wanted to separate the solid yeast from the solution. Figure 3 shows the apparatus used. What is missing from the apparatus in Figure 3?... (Total 4 marks) Page 6
Yr Chemistry Foundation Half term mock paper 2 M/S Multiple choice questions:. C 2H 6 mark.2 Alkanes mark.3 Cracking mark Structured Questions M.(a) cotton wool all points correct ± ½ small square allow mark if 5 or 6 of the points are correct 2 best fit line must not deviate towards anomalous point (c) (mass) 2. (g) allow ecf from drawn best fit line (time) 00 (s) (d) a gas is produced which escapes from the flask (e) 0.07 (g / s) allow ecf answer correctly calculated to 2 decimal places (f) (g) collect the gas in a gas syringe measured the volume of gas allow carbon dioxide for gas allow for mark collected gas or counted bubbles The particles have more energy The particles move faster [4] Page 7
M2.(a) sulfur / sulphur / S / S(s) as the temperature increases, the rate of reaction increases allow two correct values for rate quoted (from graph) at different temperatures the rate of increase increases or there is an exponential relationship accept the rate of reaction increases slowly (from 20 C to 50 C) then increases more rapidly for 2 marks answer MUST be based on rate / speed of reaction (c) (i) any two from: temperature (of the reactants) concentration of hydrochloric acid volume of hydrochloric acid volume of sodium thiosulfate the (size / darkness / thickness of the) cross total volume of solution. if no other marks gained, allow mark for: rate of stirring OR amount of hydrochloric acid / sodium thiosulfate OR volume of solution 2 (because as the concentration increases) the number of particles per unit volume increases or particles are closer together. idea of more particles in a given space is required for the first mark. ignore references to area. (therefore) the frequency of (successful) collisions increases allow increased chance / probability of collisions number of collisions increases is insufficient here. must mention per unit time or frequency. ignore speed of collisions. if reference to space and time missing from M and M2 but they are otherwise correct, then award mark. so the number of particles (per unit volume) doubles or (the frequency of) collisions doubles. students can score 2 marks for a qualitative explanation; the third mark is for a quantitative explanation. M3.(a) (i) hydrogen / H and carbon / C answers can be in either order if letters given, must be capital H Page 8 [8]
CnH2n+2 (most) crude oil vaporises / evaporates or crude oil enters as a vapour (vapour) cools as it rises up the tower / column or tower / column cooler at the top or negative temperature gradient the fractions have different boiling / condensation points / ranges accept the larger the molecules, the higher the boiling point / condensation point so they will condense at different levels in the tower allow will collect at different levels if condensation mentioned allow will condense to give different fractions if no other mark is gained allow mark for mention of heating (c) (i) C8H8 if one answer is given C8H8 is the only acceptable answer credit any correct combination of alkanes and alkenes, eg C5H2 and C3H6 hot / high temperature accept any temperature in the range 300 900 C heat is insufficient a) (i) high temperature catalyst accept a named catalyst alumina or zeolites or aluminosilicates or broken pot ignore other named catalysts allow (mixing with) steam as an alternative to second marking point ignore pressure allow heating / hot / 250-900 C catalyst or steam allow named catalyst eg zeolite, Al 2O 3, silica, ceramic allow in the absence of air / oxygen ignore any references to pressure [9] colourless allow decolourised ignore clear / discoloured Page 9
(iii) (i) 20.3(0) (kj) if answer incorrect allow mark for 24.36/.2 2 (iii) use a lid allow insulate beaker or use draught shield reduce energy / heat loss ignore references to thermometer or repeats or distance of flame or loss of water vapour allow stir to distribute energy / heat allow use a metal can as it s a better conductor carbon/soot ignore tar, smoke (produced by) incomplete combustion allow from a limited supply of oxygen/air (iv) hexane gives out the greatest energy (per.0 g) ignore more energy hexane produces the least smoke / carbon / soot allow has the cleanest flame ignore less smoke / carbon / soot (c) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also apply a best-fit approach to the marking. Level 3 (5 6 marks): Descriptions of advantages and disadvantages that are linked to their own knowledge. Level 2 (3 4 marks): Descriptions of an advantage and a disadvantage with some use of their knowledge to add value. Level ( 2 marks): Statements made from the information that indicate whether at least one statement is an advantage or a disadvantage or a linked advantage or disadvantage 0 marks: No relevant content Page 20
Examples of the added value statements and links made in the response could include: Note that link words are in bold; links can be either way round. Accept reverse arguments and ignore cost throughout. Advantages of using hydrogen: Combustion only produces water so causes no pollution Combustion does not produce carbon dioxide so this does not contribute to global warming or climate change Combustion does not produce sulfur dioxide so this does not contribute to acid rain Incomplete combustion of petrol produces carbon monoxide that is toxic Incomplete combustion of petrol produces particulates that contribute to global dimming Petrol comes from a non-renewable resource but there are renewable/other methods of producing hydrogen Hydrogen releases more energy so less fuel needed or more efficient Disadvantages of using hydrogen: Hydrogen is a gas so is difficult to store or transfer to vehicles Hydrogen gas is very flammable so leaks cause a greater risk of explosion Most hydrogen is produced from fossil fuels which are running out Cannot be used in existing car engines so modification / development or replacement is needed Lack of filling stations so difficult to refuel your vehicle 6 [8] a) (i) C2H4 poly(ethene) (i) is not biodegradable (iii) not enough landfill sites / space accept landfill sites are filling up or plastics remain for years or plastics not broken down ignore cost / waste of resources / not biodegradable / wildlife recycle / burn accept reduce the amount of packaging used ignore reused [5] M6. (a) (improve) appearance allow add colour allow these food colourings have not been proven to cause hyperactive behaviour in young children do not accept taste / flavour / preservatives ignore reference to E-numbers X (c) any three from: Page 2
S contains six / 6 colourings P contains five / 5 colourings if neither of first 2 bullet points given allow mark for S contains more colours than P or converse both S and P contain the same five / 5 colourings both contain W and Y both sweets (may) cause hyperactivity ignore unsafe neither contain X and Z 3 [5] M7.(a) Air 2 Steel Allow mark for the correct meanings linked to context but incorrect way around (c) Damp litmus paper turns white (d) Iron(III) [6] M8.(a) copper (II) blue iron (III) brown more than one line from any box negates the mark aluminium Page 22
allow correct answer shown in box if answer line blank (c) (i) yellow allow orange lilac allow purple (iii) one colour masks the other allow colours mixed [6] M9.(a) fermentation (i) turns cloudy / milky / white ignore bubbles because carbon dioxide is produced allow CO 2 produced filter paper [4] Page 23