Year 9 Science. 9C5: Energy Changes in Reactions and the Reactions of Metals. Home-Learning Challenge

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1 Year 9 Science 9C5: Energy Changes in Reactions and the Reactions of Metals Home-Learning Challenge Name: Form:

2 9C5 Module Overview and Home-Learning Subject: Science - Chemistry Year: 9 Half-Term: 1, 2 or 3 Topic: Energy changes in reactions and reactions of metals Module Overview: Endothermic and exothermic reactions Reactions of metals oxidation Reactions of metals with acid Reactions of metals with water The reactivity series of metals Displacement reactions Extracting metals Assessment: 1. Completion of an extended written task. This will take place in lessons and will be assessed based on the quality of the writing as well as the scientific content. Students will be given formative feedback on this piece of work and will be expected to re-draft it based on the feedback. 2. An end of module test involving short answers to exam questions related to the topics studied in the module. Students will be given the date of this test in advance by their teacher and will be expected to revise for it independently (see attached revision list). Home-Learning: Completion of tasks: All students are expected to complete the bronze level tasks. These are designed to consolidate students knowledge of the key concepts met in the unit. Students who complete the all the bronze level tasks to a suitable standard will be rewarded with one house point. We would expect most students to attempt the silver level tasks. These tasks are designed to deepen the students understanding of the concepts met in the unit. Students who complete the all the silver level tasks to a suitable standard will be rewarded with two house points. We would expect some students to attempt the gold level tasks. These tasks are designed to challenge the students and extend their knowledge beyond what they may have learnt in class. Students who complete the all the gold level tasks to a suitable standard will be rewarded with three house points. Students are expected to be familiar with all the key words listed in the glossary but completion of the definitions is optional. A bonus house point will be awarded to students who complete the definitions.

3 Tasks: Task Challenge Level Task Name Date 1 Bronze Endothermic or Exothermic? 2 Bronze and Silver Why don t all metals stay shiny? 3 Bronze and Silver Acids and Metals 4 Bronze and Silver Metals and Water 5 Bronze Reactivity Wordsearch 6 Bronze and Silver Reaction or no reaction? 7 Silver Energy from Reactions 8 Gold Looking for Patterns Key Words Glossary At the back of the booklet is a list of key words for the module with space to write in definitions completion is optional but students should be familiar with these words and their definitions. Resources to help complete the tasks: CGP Revision Guide

The temperature will. decrease increase exothermic endothermic Look at the examples below which are endothermic reactions and which are exothermic?

4 Task Sheet 1 (Bronze Challenge): Endothermic or Exothermic? Use words from the box to complete the sentences. In an reaction heat energy is given out to the surroundings. The temperature will. In an reaction heat energy is taken in from the surroundings. The temperature will. decrease increase exothermic endothermic Look at the examples below which are endothermic reactions and which are exothermic? Circle the correct word for each one. A self-heating food can. A tree doing photosynthesis. endothermic exothermic endothermic exothermic A self-cooling pack used to treat injuries. A burning bonfire. endothermic exothermic endothermic exothermic

5 Task Sheet 2 (Bronze Challenge Q1-5, Silver Challenge Q6-7): Why don t all metals stay shiny? 1. Write true or false for each sentence. a) Gold doesn't lose its shine. It is very reactive. b) Iron rusts. Iron is more reactive than gold. c) Paint stops iron rusting. 2. Complete these sentences using the words below. oxidation reactive oxides energy oxygen a) When metals burn in air, they react with gas. This is called an reaction. b) Metals form compounds called metal when they react with oxygen gas. c) The more a metal is, the faster it reacts. d) The more reactive a metal is, the more it releases when it reacts. 3. Complete the word equations below. 1. tin + oxygen 2. + oxygen potassium oxide 3. + zinc oxide 4. copper + oxide 5. iron + oxygen

6 6. Read the information below. Laura heats up some magnesium in a Bunsen flame. The shiny grey metal catches fire and burns with a brilliant, white flame. When it has all burned, Laura is left with a white powder. a) Write down two things that tell Laura a chemical reaction has taken place. b) Which element, other than magnesium, takes part in the burning reaction? c) What is the name of the white powder left at the end? d) Write a word equation for the reaction that happens when Laura burns magnesium. e) Laura also tried to burn some silver in the same Bunsen flame. It did not burn. What does that tell Laura about the reactivity of silver, compared with magnesium? f) Suggest one other metal that would burn even more fiercely than magnesium. 7. Gold is found in rocks as a pure metal, which means that it is not combined with any other element. Iron can be found in the mineral haematite, which is a form of iron oxide. It is not found as pure iron. a) Which of the two metals is the more reactive? b) Why is gold used more than iron in jewellery? c) Both iron and sodium react with oxygen. Sodium releases much more energy, when it reacts, than does iron. Which of the two is the more reactive? d) Silver jewellery tarnishes in air but gold does not. What does this tell you about the reactivity of silver?

7 Task Sheet 3 (Bronze Challenge): Acids and Metals 1. Only fairly reactive metals such as and react with acid. Unreactive metals such as and do not. The reaction produces gas and a salt. acid + metal a + gas 2. How can we test for this gas? Circle the correct answer. relights a glowing splint turns limewater cloudy burns with a squeaky pop puts out a burning splint 3. Look at these test tubes. Each test tube contains some hydrochloric acid and a metal. a) Which metal is the most reactive? b) Which metal is the least reactive? c) Put the metals into order of reactivity, most reactive first. most reactive least reactive d) When metals react with acids, heat is given out and the temperature rises. i. Which metal will have the highest temperature rise? ii. Which metal will have the lowest temperature rise?

8 4. When a metal reacts with an acid, a salt and hydrogen gas are produced. A salt has two parts to its name: the first part is the name of the metal that was used, the second part comes from the acid. a) Match the name of the acid to the name ending of the salt it will produce. hydrochloric acid HCl sulfate SO4 sulfuric acid H2SO4 chloride Cl nitric acid HNO3 nitrate NO3 b) Complete the word equations below. i. iron + hydrochloric + hydrogen acid chloride ii. zinc + sulfuric + acid sulfate iii. tin + tin + acid chloride iv. + magnesium + hydrogen acid chloride Extension (Silver Challenge): Write a balanced symbol equation underneath each of the word equations above.

9 Task Sheet 4 (Bronze Challenge): Metals and Water 1. Look at these beakers. Each beaker contains water and a different metal. calcium magnesium zinc lithium a) Which metal reacted the fastest?.. How can you tell?. b) Which metal reacted the least?.. How can you tell?. c) Put the metals in order of their reactivity, most reactive first.... most reactive least reactive 2. The Alkali Metals (Group 1 on the Periodic Table) all react violently with water. 1. Match the Alkali Metal to the correct description of its reaction with water. You could watch the video at to help you. sodium Floats on the water and moves around slowly. Effervesces (fizzes and bubbles). lithium potassium Floats on the water, moves around very quickly. Effervesces (fizzes and bubbles) very rapidly. Melts into a sphere. Catches fire lilac flame. Floats on the water, moves around quickly. Effervesces (fizzes and bubbles) rapidly. Melts into a sphere. 2. Write a number (1, 2 or 3) in the box next to each metal to show the order of reactivity, e.g. write 1 next to the most reactive of the three metals.

10 3. When a reactive metal reacts with water a metal hydroxide and hydrogen gas are produced. reactive + water metal + hydrogen metal hydroxide The metal hydroxide is dissolved in the water at the end of the reaction. a) Metal hydroxides are., so, we can test for them using universal indicator. The universal indicator would turn. b) We can test for hydrogen gas using a lit splint, it will burn with a.... c) Complete the following word equations: lithium + water lithium + hydrogen. + water sodium hydroxide + potassium + water calcium hydroxide + hydrogen Extension (Silver Challenge): Write a balanced symbol equation under each word equation.

11 Task Sheet 5 (Bronze Challenge): Reactivity Wordsearch Use the clues to identify the names of 15 metals. Find the names of the metals in the wordsearch and then write the name of the correct metal in the space after each clue. The number of letters in each word is given at the end of the clue. Some of the clues include the name of the metal hidden or jumbled up work out the name by unscrambling the letters that are in italics. 1. Unreactive metal that is preferred by the police? (6) 2. Metal that bursts into flames when it reacts with water. (9) 3. Jewellery metal hidden in a packet of Persil? Very strange! (6) 4. Metal in the middle of the Reactivity Series or in jumble? (4) 5. Metal that reacts with water. Needed for healthy teeth and bones. (7) 6. The least reactive metal that you have studied in this Unit. (4) 7. Unreactive metal that is also a liquid. (7) 8. Make a metal element from the symbols for titanium and nitrogen. (3) 9. Metal that burns brightly in oxygen, but does not react with water. (9) 10. Metal that is below half way in the Reactivity Series but if you read the name differently it sounds as though it s out in front. (4) 11. Precious metal found mixed up in a plum tin. (8) 12. Reactive metal used in street lamps because it gives an orange glow. (6) 13. Metal that is quite high in the reactivity series although it often seems much lower. (9) 14. Metal which reacts with acids. It sounds as though you might wash your dishes in it. (4) 15. The least reactive metal in Group 1 of the Periodic Table. (7) S P A L U M I N I U M T O V E R E V E R P O U T S A B R I G O L D C A P D Z C R S N A L A S O D I U M I R T I L S T I N R I L T I T C I I A C Y O V E N H I U U C O P P E R U I U M X I N C M R A M U M A G N E S I U M U M

12 Task Sheet 6 (Bronze Q1-3, Silver Q4-6): Reaction or no reaction? 1. This diagram shows lead 'winning' nitrate from silver. lead silver nitrate solution crystals of silver lead nitrate solution a) This type of reaction is called: neutralisation displacement burning b) Use the diagram to help you complete this word equation: lead + silver nitrate. +. c) This reaction works because lead is: more reactive than silver as reactive as silver less reactive than silver 2. Look at this cartoon. a) Which metal is the most reactive, iron or zinc? b) Complete this word equation for the reaction. zinc + iron oxide Write true or false for each sentence. a) Less reactive metals push more reactive metals out of their compounds... b) A displacement reaction happens when a more reactive metal pushes a less reactive metal out of its compound... c) A lot of energy can be released during displacement reactions...

13 4. The list shows a reactivity series for some metals. The most reactive is on the left. aluminium magnesium zinc iron copper silver Use the metals in the list to answer the following questions: a) Circle the reactions shown below that would actually happen. A B C D E copper + magnesium oxide magnesium + copper oxide zinc + silver oxide silver + zinc oxide magnesium + copper oxide copper + magnesium oxide aluminium + iron oxide iron + aluminium oxide iron + zinc oxide zinc + iron oxide b) Aluminium oxide is sometimes called a metal ore. What are ores? c) Suggest one metal, from the reactivity series above, that you could use to extract magnesium from magnesium oxide. 5. Some metals have been known for thousands of years but others have only been discovered in the last couple of centuries. Use your knowledge of the reactivity series to explain why: Sodium was discovered in 1807 but gold was one of the earliest metals to be discovered. 6. Carbon can be used to extract copper from copper ore (copper oxide). It is mixed with the ore and heated to start the reaction. Carbon dioxide is also produced. a) What does this suggest about the position of carbon in the reactivity series? b) Write a word equation to represent the reaction between carbon and copper oxide. c) Draw a particle diagram to represent the equation shown below. C + 2CuO 2Cu + CO2

14 Task Sheet 7 (Silver Challenge): Energy from Reactions This list shows the reactivities of some metals. If you put a piece of iron into copper sulphate solution, you get iron sulphate and copper metal. This happens because the iron is more reactive than copper. The reaction produces energy, which heats up the solution. If you put copper into iron sulphate solution nothing happens because copper is less reactive than iron. 1. Look at these potential reactions - decide whether each one will or won t work. If there would not be a reaction, write no reaction, if there would be a reaction write the names of the products. The first two have been done for you. a) copper + lead nitrate solution b) zinc + lead nitrate solution c) magnesium + copper sulphate solution d) iron + lead chloride solution e) lead + zinc sulphate solution f) zinc + copper sulphate solution 2. The amount of energy given out by a displacement reaction depends on the difference in reactivity between the two metals. For instance, reaction f in question 1 will produce more energy than reaction d. Write the reactions in question 1 in order, starting with the reaction that will produce the most energy. You can just use the letters for the reactions. most energy produced least energy produced 3. Metals can also be used to produce electrical energy. a) If one electrode is made of copper, which metal should you use for the other electrode to give the highest voltage? b) Which combination of metals do you think will give the highest voltage: copper and lead, or zinc and lead?.. c) Explain your answer to part b.

15 Task Sheet 8 (Gold Challenge): Looking for Patterns When metals react with oxygen they turn into metal oxides and gain in mass. Sanjay wondered whether the gain in mass might be linked to the reactivity of the metal. Clare wondered whether there was any relationship between the gain in mass and the position of the element in the Periodic Table. They collected the data in the table and tested their ideas. All the figures in the table refer to the mass of metal oxide formed when 10 g of metal was heated and completely converted into the metal oxide. Metal Mass of oxide formed / g Increase in mass / g aluminium % increase 8.9 x 100 = Atomic number Order of reactivity 13 5 calcium copper iron lead magnesium potassium sodium zinc Work out the increase in mass for each metal (remember that you started with 10 g of each metal). Write your answers in the table. The first one has been done for you. 2. Calculate the percentage increase in mass for each metal. The first one has been done for you. % increase = increase in mass x 100 original mass 3. Plot a scatter graph showing the percentage increase in mass against the order of reactivity of the metals. Ask your teacher for graph paper and stick it in. 4. Plot a second scatter graph showing the percentage increase in mass against atomic number. 5. Were Sanjay s or Clare s ideas right? For each graph decide whether: there is a definite relationship between the variables, that applies to all the metals there is a relationship (a correlation) that applies to most of the metals and if so, which elements do not fit the trend there is definitely no relationship between the variables. Write your answers on the lined paper after the graphs. 6. What important factor has not been considered at all in this analysis that may help to explain any anomalous results?

16 Please use this space to answer questions 5 and

17 Please stick your graphs on this page.

18 Energy Changes in Reactions: Key Words Glossary endothermic exothermic Reactions of Metals: oxidation corrosion rusting effervescence sphere lilac reactivity series displacement

19 Extraction of Metals: ore native abundance mining extraction reduction smelting electrolysis

20 Useful Key Words from Year 8: chemical reaction physical change reactant product word equation symbol equation conservation of mass rate salt solution

Iron filings (Fe) 56g IRON + SULPHUR IRON SULPHIDE

Iron filings (Fe) 56g IRON + SULPHUR IRON SULPHIDE W.S.51. Chemical reactions. All of the different materials around us have been formed by chemical reactions from about one hundred simple elements. The diagram below shows a chemical reaction between the