C1 The Essential Questions

Transcription

1 C1 The Essential Questions Name... Fundamental ideas (12 marks) ALWAYS ON THE EXAM 1. Complete the sentences: (i) The atomic number of an atom is the number of... (ii) The mass number of an atom is the number of Explain why an atom has no overall charge. Use the relative electrical charges of sub-atomic particles in your explanation. 3. Explain why fluorine and chlorine are in the same group of the periodic table. Give the electronic structures of fluorine and chlorine in your explanation. 4. An aluminium atom has 13 electrons. Draw the electronic structure of an aluminium atom. 5. Name the two sub-atomic particles in the nucleus of an aluminium atom.... and... When elements react, atoms join with other atoms to form compounds. Complete the sentences. 6.. Compounds formed when non-metals react with metals consist of particles called Compounds formed from only non-metals consist of particles called.... Carbon reacts with oxygen to produce carbon dioxide (CO 2). 8 How many different elements are in one molecule of carbon dioxide? What is the total number of atoms in one molecule of carbon dioxide?... Page 1

2 Limestone (9 marks) Calcium carbonate is found in limestone. Limestone is used as a building material. Limestone is also used to make calcium oxide and calcium hydroxide. Limestone is heated to make calcium oxide. 1. The reaction to produce calcium oxide from limestone is thermal If 100 g of calcium carbonate was heated and produced 56 g of calcium oxide, calculate the mass of carbon dioxide produced.... g 3. Calcium oxide reacts with a substance to produce calcium hydroxide. Name the substance Calcium hydroxide reacts with a substance to produce calcium carbonate. Name the substance Limestone reacts with acids. Balance the chemical equation for the reaction of calcium carbonate with hydrochloric acid. CaCO3 + HCl CaCl2 + CO2 + H2O 6. Describe a test to show that carbon dioxide is produced in this reaction. Give the result of the test. 7. Buildings made from limestone are affected by the products from burning fossil fuels containing sulfur. Explain why. When a mixture of limestone and clay is heated in a rotary kiln cement is produced. Burning a mixture of methane and air heats the kiln. Clay does not decompose in the kiln. Page 2

3 8. Carbon dioxide is one of the main gases in the mixture of gases coming out of the kiln. Give two reasons why. 9. Name the other main gas in the mixture of gases coming out of the kiln. Give a reason why there is a high percentage of this gas in the mixture of gases coming out of the kiln Limestone contains calcium carbonate (CaCO3). Name the type of reaction that takes place when calcium carbonate is heated strongly. Name the products formed. ON LAST 4 YEARS 11. When potassium carbonate is heated there is no change in the mass of the solid. Suggest why. (3) 12. What are the two raw materials used to make cement? Cement is mixed with three substances to make concrete. Choose from the list the 3 substances used. crushed rock iron ore quicklime sand slag soda water Why do farmers sometimes add calcium hydroxide to acidic soil? Page 3

4 Metals (x marks) - Summary Remember you are given the reactivity series in the exam for a reason!! Metals more reactive than carbon are extracted by:... Advantages: Disadvantages:. Metals with reactivity in between C and H are extracted by:... Advantages: Disadvantages:. Iron oxide is reduced with carbon in a. Metals less reactive than hydrogen can be found naturally as..... Copper Why are lots of new methods of extracting copper being developed? Smelting. Electrolysis.. Bioleaching. Phytomining.. Scrap Iron Iron Why don t we use pure iron?.. Why don t we use iron straight from the blast furnace?. What are low carbon steels good for?.. What are high carbon steels good for?. What are stainless steels good for?... These are alloys. How are alloys different from pure metals? Properties of transition metals General properties.. Uses of Cu Properties making it useful Uses of Al or Ti Properties making it useful. Page 4

5 Metals 1. What is the meaning of the term ore? What is meant by an alloy? Explain why the recycling of iron is necessary for sustainable development. Iron ON THE LAST 2 YEARS (3) 1. Haematite is an ore of iron. Haematite contains iron oxide, Fe 2O 3. Iron can be produced by reacting iron oxide with carbon in a blast furnace. What type of reaction produces the iron? Pure iron is relatively soft and not very strong. The iron from the blast furnace is very hard and brittle. It contains about 4% carbon and is used as cast iron. NOT ON LAST 3 YEARS 2. Explain the differences in the properties of pure iron and cast iron by referring to the diagrams. 3. Give one advantage of using this alloy instead of pure iron... (3) Titanium/Aluminium 1. Aluminium and copper are good conductors of electricity. State one property that makes aluminium more suitable than copper for overhead cables. Page 5

6 Copper NOT ON THE LAST 2 YEARS, BUT ON THE 3 YEARS BEFORE HOT QUESTION 1. Copper can be extracted from solutions of copper salts by adding scrap iron. Explain why. 2. Copper extracted by smelting is about 99% pure. The 99% pure copper produced by smelting is purified to % pure copper by electrolysis. Explain why copper is purified to %. 3. Describe what happens to the copper ions during electrolysis. One way to extract the copper from land that contains low percentages of copper sulfide is by bioleaching. Bioleaching uses bacteria. The bacteria produce a solution of copper sulfate. It is possible to get copper from a solution of copper sulfate using scrap iron. A new way to extract the copper from land that contains low percentages of copper sulfide is phytomining. Phytomining uses plants. Plants are grown on this land and absorb copper compounds through their roots, before being burnt and the copper-rich ash collected. 4. Give two advantages of phytomining compared to the traditional method. 5. Suggest one disadvantage of phytomining compared to the traditional method. 6. Suggest two reasons why copper from these areas of land is not extracted by smelting. Page 6

7 Crude Oil and Fractional Distillation ON MOST YEARS Complete the sentence. 1. Hydrocarbons contain the elements... and... only. 2. What are alkanes? Complete the general formula of alkanes: Cn.. 4. Describe how crude oil is separated into fractions..hot QUESTION 5. What is a fraction?... Burning alkanes 1. Name the reaction that releases energy from a fuel such as gasoline (petrol).... Alkanes in petrol burn in air. The equations represent two reactions of hexane burning in air. (4) Reaction 1 2C 6H O 2 12CO H 2O Reaction 2 2C 6H O 2 12CO + 14H 2O Reaction 2 produces a different carbon compound to Reaction Name the carbon compound produced in Reaction Give a reason why the carbon compounds produced are different. 4. Give a reason why sulfur dioxide is produced in a petrol engine. 5. State how nitrogen oxides are produced in a petrol engine. Page 7

8 Cracking Compounds C 2H 4 and C 8H 18 are produced by cracking C 14H 30 C 14H 30 3C 2H 4 + C 8H Complete the sentence: Cracking is a type of thermal Give two conditions for cracking Suggest why air must not enter the cracking reactor Suggest a method that can be used to separate C 2H 4 and C 8H Explain why C 8H 18 has a lower boiling point than C 14H Dodecane (C 12H 26) from crude oil is cracked to produce ethene (C 2H 4). 6. Complete the equation for this reaction. C 12H 26 2 C 2H What the uses of the alkanes formed from cracking?.. 8. What the uses of the alkenes formed from cracking?.. Alkenes A molecule of ethene (C 2H 4) is represented as: 1. When ethene is shaken with bromine water, the bromine water turns from orange to Draw the displayed structure of a butene (C4H8) molecule. Page 8

9 Polymers NOT MUCH ON THIS OVER LAST 3 YEARS 1. Describe how molecules of butene (C4H8) form poly(butene). 2. Complete the structure of the polymer in the equation. 3. Complete the equation to represent the formation of poly(propene) from propene. (3) 4. Some carrier bags are made from poly(ethene). Some carrier bags are made from cornstarch. Suggest two benefits of using cornstarch instead of poly(ethene) to make carrier bags. Tablet containers are often made from two different polymers, polyethene and polypropene. Used tablet containers could be disposed of in a landfill site or could be recycled. 5. Suggest two reasons why disposing of the tablet containers in a landfill site could cause problems Suggest one reason why recycling the tablet containers would be difficult. Page 9

10 Ethanol ON 4 OF LAST 5 YEARS There are two different ways to produce ethanol: using ethene from crude oil using sugar from plants. 1. Ethanol is produced from ethene by hydration in the presence of a catalyst. What is hydration? 2. Ethanol is produced by fermentation of sugar cane. Describe how the process of fermentation is done. 3. Give one advantage that fermentation has over hydration. 4. What advantages to a manufacturer of ethanol, does hydration have over fermentation? 5. Carbon neutral fuels do not increase the amount of carbon dioxide in the atmosphere. Suggest why using a biofuel, such as ethanol, is thought to be carbon neutral. Plant Oils (20 marks) Useful materials, including foods and fuels, are produced from plants. Some plants have seeds that contain vegetable oils. 1. Give one reason why vegetable oils are important foods and fuels. 2. State the two main stages used to extract a sample of vegetable oil from seeds. Page 10

11 3. One property of vegetable oil gives the oil an advantage over water for cooking foods. Explain how. Vegetable oils and water do not mix. An emulsion is made by shaking a vegetable oil and water with an emulsifier, as shown below. 4. Explain how the emulsifier molecules are able to produce an emulsion that is a stable mixture containing the vegetable oil and water. Use the diagram of the emulsifier molecule to help you to answer this question. NOT ON FOR 3 YEARS 5. Olive oil contains 89% unsaturated fats and 11% saturated fats. What is the test and the result for unsaturated fats? ON EVERY YEAR (4) 6. Olive oil is hardened to make margarine. Describe the reaction and conditions needed to harden a vegetable oil. ON LAST YEAR 7. A student said that hardening would make olive oil healthier. Is this student s hypothesis correct? Explain your answer in terms of what happens in the hardening process. (3) Page 11

12 Earth Science Planet Earth NOT ON LAST YEAR _ HOT QUESTION 1. Describe how and explain why continental drift takes place. Include the names the different parts of the Earth in your answer. 2. Alfred Wegener put forward his idea of continental drift in Why did most scientists in 1915 not accept Wegener s idea of continental drift? (5) 3. Suggest two pieces of evidence that Wegener used to show that the continents had once been joined The theory of plate tectonics is used to explain why earthquakes occur. Explain how earthquakes occur. 5. Suggest why it is difficult to predict when an earthquake will occur. 6. Why does Iceland have volcanoes? 7. Suggest one reason why scientists do not know exactly when volcanoes will erupt. Page 12

13 Earth Science Carbon Dioxide NOT ON LAST YEAR _ HOT QUESTION The amount of carbon dioxide in the Earth s atmosphere has changed since the Earth was formed. The amount of carbon dioxide continues to change because of human activities. 1. Calcium carbonate contains locked up carbon dioxide. What is locked up carbon dioxide? Graph 1 shows how the percentage of carbon dioxide in the atmosphere changed in the last 4500 million years. 2 Describe how the percentage of carbon dioxide has changed in the last 4500 million years Give two reasons why the percentage of carbon dioxide has changed. Graph 2 shows how the percentage of carbon dioxide in the atmosphere changed in the last 250 years. 4. Suggest two reasons for this change Explain why some people feel we should be worried about this change Page 13

14 Earth Science Earth s Atmosphere NOT ON LAST YEAR _ HOT QUESTION 1. Explain what has happened to most of the water vapour in the Earth s early atmosphere. Scientists study the atmosphere on planets and moons in the Solar System to understand how the Earth s atmosphere may have evolved. Titan is the largest moon of Saturn. The table shows data about some substances in the atmosphere of Titan. Substance Melting point in C Boiling point in C Nitrogen Methane Argon Hydrogen Carbon monoxide There is no water on Titan. The average surface temperature on Titan is 179 C. Which of the substances in the table would form oceans on Titan? Explain your answer. Amino acids are essential to life. In the 1950s the Miller-Urey experiment showed that simple amino acids, such as glycine (NH2CH2COOH), could have been produced from the Earth s early atmosphere. The Miller-Urey experiment showed that simple amino acids could be produced by reactions between hydrocarbons, ammonia and water. Explain how the Miller-Urey experiment suggests that reactions between the substances in Titan s atmosphere could also produce simple amino acids. (4) Page 14