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Name: _________________________ Teacher: ______________ The Periodic Table Early Periodic Table Fill in the gaps for the early arrangement of the Periodic table. Newlands attempted to arrange the elements in the Periodic table in order of their _______________ ____________. He noticed that every eighth element had similar _____________________. He called this discovery the law of _________________. __________________ rearranged the order of the periodic table so that there were gaps for elements that had not yet been discovered. However, some elements were still not appropriately place. The modern Periodic table is arranged in order of ____________________ _________________ so that their properties are grouped together. atomic number atomic mass octaves properties Mendeleev Group 1 Group 1 metals are called the alkali metals. They all react with water. Reactivity increases down the group. Draw the electronic structures of lithium, sodium and potassium below and explain why reactivity with water increases down the group. K Na Li The group 1 metals react with water to produce an alkali and hydrogen gas: Alkali Metal + Water Alkali Metal Hydroxide + Hydrogen Write the word equations for the reactions of lithium, sodium and potassium with water in the space below. Group 7 Group 7 elements are called the halogens. Reactivity decreases down the group. Draw the electronic structures of fluorine and chlorine below and explain why reactivity decreases down the group. F Cl Transition Metals Transition metals are found in the block in the _____________ of the Periodic table. They have lower densities compared to the alkali metals. Transition metals are not as reactive as alkali metals. Many transition metals can form ions with more than one charge and have coloured compounds. For example Fe2+ forms _________ coloured compounds. Fe ___ forms brown coloured compounds. Exam Questions Q1. This question is about the periodic table. Use the Chemistry Data Sheet to help you answer these questions. (a) Complete the sentences. Elements in the periodic table are arranged in order of atomic ...................................... . The elements in Group .................... are called the noble gases. (2) (b) Calcium (Ca) is in Group 2. Name one other element in Group 2. ........................................................................................................................ (1) (c) Draw a ring around the correct answer to complete each sentence. (i) an alkali metal. Sodium (Na) is a non-metal. a transition metal. (1) (ii) an alkali metal. Nickel (Ni) is a non-metal. a transition metal. (1) (d) In 1869 Mendeleev produced his periodic table. Why did Mendeleev leave gaps in his periodic table? ........................................................................................................................ ........................................................................................................................ (1) (Total 6 marks) Q2. Sodium is a Group 1 element. (a) (i) A small piece of sodium is added to some water containing Universal Indicator solution. Describe what you would see happening. .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... .......................................................................................................................................... ........................................................................................................................................... (3) (ii) Complete and balance the equation for the reaction of sodium with water. ......Na + ......H2O → ........................ + H2 (2) (b) Francium is the most reactive element in Group 1. Explain why in terms of electronic structure. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... (3) (c) The transition elements have different properties from the elements in Group 1. Give two of these different properties of transition elements. 1 ..................................................................................................................... ........................................................................................................................ 2 ..................................................................................................................... ........................................................................................................................ (2) (Total 10 marks) Q3. The halogens are in Group 7 of the periodic table. (a) Why, in terms of electrons, are the halogens in Group 7? ....................................................................................................................................................... (1) (b) Sea water contains bromide ions (Br -). The bromide ions can be changed to bromine by bubbling chlorine gas into sea water. Chlorine is able to displace bromine from sea water because chlorine is more reactive than bromine. 2Br -(aq) + Cl2(g) → Br2(g) + 2Cl -(aq) Explain, in terms of electrons, why chlorine is more reactive than bromine. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. .................................................................................................................................................. (3) (Total 4 marks) Water Hard and Soft Water We can tell the difference between soft water and hard water because soft water readily forms a __________________ with soap solution. Hard water will form __________ with soap solution. Hard water is hard because it contains __________________ ions (Ca2+) and magnesium ions (______). These ions are contained in the water from when it runs over rocks and dissolves them. When hard water is mixed with soap solution it will form a ___________. Temporary Hard Water Temporary hard water contains calcium hydrogen carbonate (specifically the hydrogen carbonate ion HCO3¯). When temporary hard water is heated the hydrogen carbonate ions decompose to form carbonate ions (CO32¯), or calcium carbonate. We see this form in our kettle as _______________________. Permanent Hard Water Permanent hard water contains dissolved sulfate ions which do not decompose when heated. To soften hard water we can either add sodium carbonate to it or pass it through an ion exchange column. Upon adding sodium carbonate to hard water, the carbonate ions will react to form insoluble precipitates of calcium carbonate or magnesium carbonate. As there are no longer dissolved calcium or magnesium ions the water is no longer hard. We can remove the insoluble precipitate by _____________________. The insoluble precipitate is called lime scale, which can clog up pipes in washing machines. A simplified ion exchange column is shown below. Describe how it works in the space to the right. Put the following statements into the table below for hard and soft water. • • • • • There is less heart disease in these areas. It is easier to form a soap lather in these areas. The central heating systems have their pipes narrowed by scale in these areas. You need less washing powder for the same amount of washing in these areas. You rarely, if ever, need to descale your kettle in these areas. Soft Water Hard Water Purifying Water To obtain water of the correct quality the following needs to be completed: Filter to remove any insoluble waste. Add a coagulant (eg. aluminium) to precipitate dissolved metal ions from the solution. Add _________________ to kill bacteria. Water filters can be used to improve the taste of water by removing some dissolved substances. Water filters are made from carbon. Exam Questions Q4. Some people use water filters because they are concerned about the quality of drinking water. (a) Draw a ring around the correct answer to complete each sentence. carbon. (i) One of the active chemicals in many water filters is magnesium. sulfur. (1) (ii) In many areas of the United Kingdom the water is hard. bromide The hardness in water is caused by calcium ions. hydrogen (1) (b) Describe and give the result of a test to show that some drinking water is hard. Test ................................................................................................................ ........................................................................................................................ Result of test ................................................................................................. ........................................................................................................................ (2) (c) State and explain one benefit of drinking hard water. ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ (2) (Total 6 marks) Q5. Water is a natural resource. Drinking water in some parts of the UK is soft, but in other parts drinking water is hard. Calcium ions in water cause water to be hard. There are two types of hard water, permanent hard water and temporary hard water. • Permanent hard water can be caused by calcium sulfate (CaSO4) dissolved in the water • Temporary hard water can be caused by calcium hydrogencarbonate (Ca(HCO3)2) dissolved in the water (a) Temporary hard water causes the formation of scale on heating elements. (i) Explain how scale forms on heating elements. ...................................................................................................................................................... ...................................................................................................................................................... ...................................................................................................................................................... (2) (ii) Suggest why scale on heating elements causes problems. .................................................................................................................................................... .................................................................................................................................................... (1) (b) Permanent hard water can be softened. (i) Explain how adding sodium carbonate (Na2CO3) softens permanent hard water. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... (2) (ii) Explain how a water filter containing an ion exchange resin softens permanent hard water. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... (2) (Total 7 marks) Q6. Good quality water is needed for a healthy life. In the United Kingdom, obtaining safe water for drinking is as simple as turning on a tap. The water is made safe to drink by water companies. However, in many parts of Africa and Asia, water used for drinking is contaminated and untreated. It is estimated that 2.2 million people die each year as a result of drinking contaminated water. Efforts are being made to solve this problem and more water is being treated. Describe how water in the United Kingdom is treated. Explain how this makes it safe to drink. ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ (Total 3 marks) Calculating and Explaining Energy Changes Calorimetry The amount of energy released when substances burn can be measured by simple calorimetry. An experimental set up is shown in the diagram below. Describe what is happening in the space to the right. We can calculate the amount of energy released by the fuel burned using the following equation: Q = m c ∆T change in temperature of the water heat energy released (J) mass of water in beaker specific heat capacity = 4.2 Hydrogen as a Fuel Hydrogen can be burned as a fuel in combustion reactions: Hydrogen + Oxygen Water Describe why hydrogen would be a good fuel to use in an engine. Calculating Bond Energies During a reaction energy must be taken in to break bonds. Energy is also released when new bonds form. The overall energy change tells us whether the reaction is exothermic or endothermic. To calculate the overall energy change we must add together all of the energy needed to break each bond and minus all of the energy released when bonds formed. Complete the example question below: The table shows the values of some bond energies. Bond Bond energy in kJ per mole H—H Cl—Cl H—Cl 436 242 431 Use the values in the table to calculate the overall energy change (∆H ) for the reaction. H2(g) + Cl2(g) 2 HCl(g) ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... Energy change (∆H ) = ......................... kJ per mole Your answer should be -184 kJ/mol If the amount of energy released from bonds forming is greater than the amount of energy taken in then the reaction is ________________________. If the amount of energy taken in to break bonds is greater than the amount of energy released then the reaction is ______________________. Energy Level Diagrams Energy level diagrams can be used to show the relative energies of reactants and products, the activation energy and the overall energy change of a reaction. Label these on the diagram on the next page. A= B= C= D= A catalyst works by lowering the activation energy (the minimum amount of energy needed for a reaction to happen). Draw a new line on the diagram above to show what would happen is a catalyst was added. Exam Questions Q7. Hydrogen peroxide decomposes slowly to give water and oxygen. The reaction is exothermic. 2H2O2 (a) → 2H2O + O2 In an exothermic reaction, energy is given out. Draw a ring around the correct answer to complete the sentence. goes down. In an exothermic reaction, the temperature goes up. stays the same. (1) (b) The energy level diagram for this reaction is shown below. The energy changes, A, B and C, are shown on the diagram. Use the diagram to help you answer these questions. (i) Which energy change, A, B or C, shows the activation energy? (1) (ii) Which energy change, A, B or C, shows that this reaction is exothermic? (1) (iii) Hydrogen peroxide decomposes quickly when a small amount of manganese(IV) oxide is added. Draw a ring around the correct answer to complete each sentence. a catalyst. Hydrogen peroxide decomposes quickly because manganese(IV) oxide is an element. a solid. activation energy. The manganese(IV) oxide has lowered the boiling point. temperature. (2) (c) A student did an experiment to find the amount of energy produced when hydrogen peroxide solution is decomposed using manganese(IV) oxide. The apparatus the student used is shown in the diagram. The student first measured the temperature of the hydrogen peroxide. Then the student added the manganese(IV) oxide, stirred the mixture and recorded the highest temperature. (i) Suggest why the student stirred the mixture before recording the highest temperature. ................................................................................................................................................... (1) (ii) The biggest error in this experiment is heat loss. Suggest how the student could change the apparatus so that less heat is lost. .................................................................................................................................................... (1) (Total 7 marks) HYDROGEN FUEL OF THE FUTURE Q8. It has been suggested that hydrogen could be used as a fuel instead of the fossil fuels that are used at present. The equation below shows how hydrogen burns in air. 2H2 + O2 → 2H2O + heat The hydrogen would be made from water using energy obtained from renewable sources such as wind or solar power. The water splitting reaction requires a lot of energy. (a) Hydrogen was successfully used as a fuel for a Soviet airliner in 1988. Why would hydrogen be a good fuel for use in an aeroplane? ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (Total 2 marks) Q9. Hydrogen peroxide is often used to bleach or lighten hair. Hydrogen peroxide slowly decomposes to produce water and oxygen. (a) The equation for the reaction can be represented using structural formulae. 2H–O–O–H 2H–O–H + O=O Use the bond energies in the table to help you to calculate the energy change for this reaction. Bond Bond energy in kJ per mole H–O 464 O–O 146 O=O 498 ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ Energy change = ........................................ kJ (3) (b) Explain, in terms of bond making and bond breaking, why the reaction is exothermic. ............................................................................................................................................... ............................................................................................................................................... (1) (Total 4 marks) Identifying Ions Flame Tests Spills have been soaked in solutions containing the following metal ions overnight. The colours of the flames are as follows: Positive Ion Colour of Flame Lithium Sodium Potassium Calcium Barium Precipitation Reactions with Sodium Hydroxide Add solutions containing the positive ions to a small amount of sodium hydroxide and note the colour of the precipitate. Add an excess of sodium hydroxide to note any changes. Positive ion Observation with NaOH… Small amount Excess Magnesium Calcium Aluminium Copper Iron (II) Iron (III) Precipitation Reactions of the Halide Ions with Silver Nitrate Add 1cm3 of nitric acid to the halide solution to remove any unwanted ions. Add a small amount of silver nitrate to the halide solution and note the colour of the precipitate formed. Halide Ion Colour of Precipitate Chloride Bromide Iodide Identifying Sulfate Ions Add 1cm3 of hydrochloric acid to your sulfate solution to remove any unwanted ions. Add a small amount of barium chloride to your solution and note any changes. Negative Ion Sulfate Observation with barium chloride Identifying Carbonate Ions Place a spatula of the metal carbonate on a heat proof mat. Add a few drops of acid and observe any changes. Negative Ion Observation with acid Carbonate The gas being released in this reaction is ___________________________________________________ To test for this gas we use _______________________________ and we are looking for it to turn ____________________. Testing Your Knowledge: What am I? (Ions) 1. When sodium hydroxide solution was added to a solution of the compound, a white precipitate was formed. On adding excess sodium hydroxide solution, the precipitate was insoluble. When the solution was tested in a flame, the colour was brick red. I am _____________________________. 2. When sodium hydroxide solution was added to a solution of the compound, a white precipitate was formed. On adding excess sodium hydroxide solution, the precipitate was insoluble. This solution did not change the colour of a flame. I am ____________________________________________. 3. The solution forms a green precipitate on the addition of a small amount of sodium hydroxide. I am ___________________________. Testing Your Knowledge: What am I? (Compounds) 4. When the solution was tested in a flame, the colour was lilac. Adding acidified silver nitrate to the solution produced a cream precipitate. I am __________________________________________. 5. When sodium hydroxide solution was added to a solution of the compound, a white precipitate was formed. On adding excess sodium hydroxide solution, the precipitate was soluble. Adding acidified silver nitrate to the solution produced a white precipitate. I am _____________________________ ______________________________. 6. When sodium hydroxide solution was added to a solution of the compound, a blue precipitate was formed. Hydrochloric acid was added to a solid form of this compound and fizzing was observed. I am _____________________________________________. Exam Question Q10. A student investigated an egg shell. (a) The student did some tests on the egg shell. The student’s results are shown in the table below. Test 1 Dilute hydrochloric acid was added to the egg shell. Observation A gas was produced. The egg shell dissolved, forming a colourless solution. (i) 2 A flame test was done on the colourless solution from test 1. The flame turned red. 3 Sodium hydroxide solution was added to the colourless solution from test 1. A white precipitate formed that did not dissolve in excess sodium hydroxide solution. 4 Silver nitrate solution was added to the colourless solution from test 1. A white precipitate formed. The student concluded that the egg shell contains carbonate ions. Describe how the student could identify the gas produced in test 1. ................................................................................................................................................ ................................................................................................................................................ ................................................................................................................................................ (2) (ii) The student concluded that the egg shell contains aluminium ions. Is the student’s conclusion correct? Use the student’s results to justify your answer. ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... (2) (iii) The student concluded that the egg shell contains chloride ions. Is the student’s conclusion correct? Use the student’s results to justify your answer. ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... (2) (Total 6 marks) Titrations Titration Method Titrations can be used to measure the volumes of acid and alkali solutions that react with each other with a suitable indicator present. Write a method for a titration, using all of the equipment shown, in the space below: ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ ........................................................................................................................................................ Titration Calculations We can calculate the unknown concentration of a solution following this method. 1. Write out what you have of each reactant. Don’t forget to convert cm3 to dm3 by dividing by 1000. 2. Calculate the moles of the reactant that you have the volume and concentration for using the equation moles = CxV. 3. Use the ratio of the balanced equation to find the number of moles in the reactant with the unknown concentration. 4. Rearrange the equation to find the unknown concentration: C = moles ÷ V Exam Question Q11. In 1916, during the First World War, a German U-boat sank a Swedish ship which was carrying a cargo of champagne. The wreck was discovered in 1997 and the champagne was brought to the surface and analysed. (a) 25.0 cm3 of the champagne were placed in a conical flask. Describe how the volume of sodium hydroxide solution needed to react completely with the weak acids in 25.0 cm3 of this champagne can be found by titration, using phenolphthalein indicator. Name any other apparatus used. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (4) (b) The acid in 25.0 cm3 of the champagne reacted completely with 13.5 cm3 of sodium hydroxide of concentration 0.10 moles per cubic decimetre. Calculate the concentration in moles per cubic decimetre of acid in the champagne. Assume that 1 mole of sodium hydroxide reacts completely with 1 mole of acid. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... Concentration = ......................... moles per cubic decimetre (2) (c) Is analysis by titration enough to decide whether this champagne is safe to drink? Explain your answer. ..................................................................................................................................... ..................................................................................................................................... (1) The Haber Process The raw materials for making ammonia are ________________ and __________________. ____________________ is obtained from the air. ___________________ is obtained from the reaction of methane with steam. Write the word and symbol equation for the production of ammonia below. Don’t forget that it is a reversible reaction. A diagram of the Haber Process is shown below. Describe what happens in the space to the right. Conditions used in the Reactor The temperature used in the Haber process is 450°C. This is a compromise between the rate of reaction and the yield. The higher the temperature the ________________ the rate of reaction, but the lower the yield. The pressure used in the Haber process is 200atm. This is a compromise between the yield and the cost of the equipment. The higher the pressure the higher the yield of ammonia, but the higher cost as the equipment needs to be reinforced. Equilibrium In a reversible reaction, as the reactants get used up the forward reaction rate slows down. As more product is formed, the reverse reaction rate speeds up. Eventually both reactions will be going at exactly the same rate, so the concentrations of the reactants and products won’t change. It will seem as though nothing is happening. We call this a dynamic equilibrium. Once equilibrium is reached, it is possible to change it in favour of producing more products. To do this, we can change either the temperature or the pressure. Increasing the pressure will shift the equilibrium to the side with fewer gas molecules to oppose the change and reduce the pressure. Explain what will happen in the reaction to produce ammonia. N2 + 3 H2 2 NH3 Increasing the temperature means adding heat to the reaction. The endothermic direction will be favoured to try to oppose this change and lower the temperature. Explain what will happen in the reaction to produce ammonia. exo N2 + 3 H2 endo 2 NH3 Exam Questions Q12. The flow diagram shows the Haber process. In the Haber process, ammonia (NH3) is produced from nitrogen (N2) and hydrogen (H2). (a) Which raw material is nitrogen obtained from? ............................................................................................................................................... (1) (b) What is the purpose of Pipe X? ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... (2) (c) Balance the chemical equation below for the production of ammonia. N2 + ..........H2 ..........NH3 (1) (d) A temperature of 450°C is used in the reactor. The reaction of nitrogen with hydrogen is reversible. The forward reaction is exothermic. Explain why a temperature of 450°C is the optimum temperature for the Haber process. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (2) (Total 6 marks) Q13. An exothermic reaction takes place when nitrogen reacts with hydrogen to make ammonia. The reaction can be represented by this equation. N2 (g) (a) + 3H2 (g) 2NH3 (g) State and explain: (i) how a decrease in temperature would affect the yield of ammonia ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (ii) how an increase in pressure would affect the yield of ammonia. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (Total 4 marks) Organic Chemistry Alcohols Alcohols contain the functional group –OH and have the suffix –ol when naming. The general formula for alcohols is: CnH2n+1OH Draw the structures of methanol, ethanol and propanol. Methanol (CH3OH) Ethanol (C2H5OH) Propanol (C3H7OH) Alcohols dissolve in water to form a neutral solution because they have covalent bonds. They react with metals in the same way as water, producing hydrogen when reacted with sodium. Alcohols combust in the same way as alkanes; reacting with oxygen to form carbon dioxide and water. Write the word and balanced symbol equations for the combustion of methanol, ethanol and propanol. Methanol: Ethanol: Propanol: Carboxylic Acids Ethanol can be oxidised to form ethanoic acid (a carboxylic acid). Carboxylic acids have the functional group –COOH and the suffix –oic acid. Draw the structures of methanoic acid, ethanoic acid and propanoic acid. Methanoic acid (HCOOH) Ethanoic acid (CH3COOH) Propanoic acid (CH3CH2COOH) Carboxylic acids react with metal carbonate in the same way as other acids: Metal Carbonate + Ethanoic Acid Metal Ethanoate + Carbon Dioxide + Water Write the word equation for the reaction of calcium carbonate and ethanoic acid below: Carboxylic acids dissolve in water to form an acidic solution. They are considered to be weak acids as they only partially dissociate when dissolved in water. This means that not all of the carboxylic acid molecules dissociate into their ions: CH3COOH H+ + CH3COO¯ Strong acids such as hydrochloric acid fully dissociate when dissolved in water: HCl H+ + Cl¯ This means that every HCl molecule will dissociate to form the positive and negative ions. Strong acids have low pH’s of 1. Weak acids have higher pH’s of 5 or 6. Esters Carboxylic acids and alcohols react together in the presence of an acid catalyst to produce esters. Esters have the functional group –COO–. Ethyl ethanoate is the ester formed from ethanol and ethanoic acid. Draw the structure of ethyl ethanoate below: Esters have distinctive smells and are used as flavourings and perfumes. Exam Questions Q14. The structures shown are of the first two members of a homologous series of organic compounds. Methanol (a) (i) Ethanol Complete the diagram for propanol, the next member of the homologous series. C―C―C Propanol (1) (ii) Which one of the statements about ethanol is correct? Tick ( ) one box. Statement Tick ( ) Ethanol dissolves in water to form a neutral solution. Ethanol reacts with sodium to produce chlorine. Ethanol does not burn in air. (1) (b) Ethanoic acid (CH3COOH) can be produced from ethanol (CH3CH2OH). (i) What type of reaction happens when ethanoic acid is produced from ethanol? ............................................................................................................... (1) (ii) State one use of ethanoic acid. ............................................................................................................... (1) (Total 4 marks) Q15. This question is about organic compounds. (a) Wine contains ethanol (CH3CH2OH). (i) Complete the displayed structure of ethanol. (1) (ii) Wine left in a glass for several days turns sour. The sour taste is caused by ethanoic acid. Complete the sentences. The ethanoic acid is produced from a reaction between ethanol and ................................................... . This type of reaction is ................................................... . (2) (b) Propyl ethanoate, a fragrance, can be produced by reacting ethanoic acid with an alcohol. Propyl ethanoate is a member of a series of organic compounds. The members of the series all have the same functional group. The displayed structure of propyl ethanoate is: (i) Draw a ring around the functional group for this series on the displayed structure of propyl ethanoate. (1) (ii) Name the series of organic compounds with this functional group. ............................................................................................................... (1) (iii) The alcohol used to make propyl ethanoate has the formula CH3CH2CH2OH Name this alcohol. ............................................................................................................... (1) (Total 6 marks) Q16. The structures shown are of the first three members of a homologous series of alcohols. (a) (i) Draw a ring around the correct general formula for alcohols. CnH2n+1OH C2nH2n+1OH CnH2n+2OH (1) (ii) What is the formula of the functional group for alcohols? ............................................................................................................... (1) (b) Ethanol is the alcohol used in alcoholic drinks. (i) When ethanol dissolves in water the solution formed is not alkaline. Tick ( ) the reason why the solution formed is not alkaline. Reason Tick ( ) Ethanol can be used as a solvent. Ethanol dissolves in water to form hydroxide ions. Ethanol has only covalent bonds in its molecule. (1) (ii) Ethanol is used as a fuel because ethanol burns in oxygen. Complete and balance the chemical equation for this reaction. C2H5OH + ................O2 → 2 CO2 + ................ (2) (c) Ethanol can be oxidised to produce the compound shown. (i) Draw a ring around the correct answer to complete the sentence. acidic. When this compound dissolves in water, the solution formed is alkaline. neutral. (1) (ii) Ethanol reacts with this compound to produce the organic compound shown. C2H5OH + CH3COOH → CH3COOC2H5 + H2O Complete the sentence. The type of organic compound produced is ......................................... . (1) (Total 7 marks) GOOD LUCK IN YOUR EXAM!
