Unit 1: Chemical Changes and Structure

1. Unit 1: Chemical Changes and Structure National Chemistry

2. Chemical Changes and Structure • Rates of Reaction • Atomic Structure • Bonding • Catalysts and Types of Reaction • Formulae, Equations and Calculations • Acids and Bases Beautiful reactions

3. Rates of Reaction

4. Lesson 1a LI: Identify the signs of a chemical reactionTitle: Signs of a chemical reaction Green – I can state that during a reaction a new substance is formed. I can identify a chemical reaction by a change in appearance or a change in energy. I can describe the difference between a chemical and physical change. Amber – I can state that during a reaction a new substance is formed. I can identify a chemical reaction by a change in appearance or a change in energy. Red – I can state that during a reaction a new substance is formed.

5. What do you know about Chemical Reactions? Fib Find the • Collect a Find the fib cards. • Working with your partner, read each card 1 at a time. • One statement on the card will be a fib, you must identify this statement. • Take a note of the card number and the fib and then move on to the next card. • Hit the buzzer when your team is finished!

7. Practical Activity 1.0Signs of a Chemical Reaction AIM: to identify the signs of a chemical reaction Method: • Stations 1 • Put a spatula tip of copper carbonate into the test tube, heat carefully with a small blue flame – ensure that the test tube is facing the wall when heating • Station 2 • Put a spatula tip of calcium in the test tube and half fill the test tube with water • Stations 3 • Quarter fill the test tube with one of the solutions and then add the second solution – do not fill the test tube by more than half • Station 4 • Put a spatula tip of calcium carbonate into the test tube and half fill the test tube with acid • Station 5 • Put a few pieces of zinc into the beaker and add a small volume of copper sulphate

8. Results: Write a conclusion stating the signs of a chemical reaction Conclusion:

9. Signs of a Chemical Reaction Chemical reactions can be identified by: • A new substance being formed • a change in appearance – a colour change • A gas is given off – fizzing or a smell is detected • A precipitation reaction occurs – a solid is formed from 2 solutions 2. A change is energy occurs • An Increase or decrease in temperature • Light or sound energy is given off

10. precipitation Colour change Increase in temperature/ light/sound given off Gas produced Decrease in temperature

11. Chemical or Physical? Physical changes are not the same as a chemical reaction. Water is still the same chemical no matter what state it is in. Physical changes involve a change in state but do not produce a new substance. They can involve a change in energy.

12. Lesson 1 Chemical and Physical reactionThink-Pair-Share • Work in pairs, collect the “Chemical and Physical Reactions” card sort. • Each take a turn to place a card in either The “physical change” pile or the “Chemical change” pile. • You should both agree before moving onto the next card, making sure you have a reason why the card belongs on this section. • Carry on until all the cards have been correctly placed. • Your teacher will discuss each card with you.

13. CHEMICAL PHYSICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL PHYSICAL CHEMICAL PHYSICAL PHYSICAL PHYSICAL CHEMICAL PHYSICAL PHYSICAL

14. Lesson 1b LI: Name compounds Title: Naming Compounds Green – I can name a compound formed from 2 elements. I can identify the elements in a compound from the name. I can name an element containing 3 elements when oxygen is one of the elements. I can identify the elements present in a compound ending in ITE or ATE. I can state the difference between compounds ending in ITE or ATE. Amber – – I can name a compound formed from 2 elements. I can identify the elements in a compound from the name. I can name an element containing 3 elements when oxygen is one of the elements. I can identify the elements present in a compound ending in ITE or ATE. Red - I can name a compound formed from 2 elements. I can identify the elements in a compound from the name.

15. Naming 2 Element Compounds When 2 or more different elements react together they form a compound. The compound is new substance and has different properties than the elements it is made from. When naming a compound the rule is (usually) that the elements on the left hand side of the periodic table come before the elements on the right hand side. The means metals are always the first part of the name and non-metals are always the second part of the name. Example 1 When sodium reacts with chlorine, the compound sodiumchloride is made. The name of the first element stays the same but the ending of the second element is changed to -IDE Example 2 Magnesium reacts with bromine to form magnesiumbromide Example 3 Potassium reacts with carbon to form potassiumcarbide Example 4 Lithium reacts with phosphorus to form lithiumphosphide

16. Identifying Elements in a Compound Use your Data Book You should always have your Data Booklet with you. The first element in the compound is easy to identify as the name is unchanged. You must use your data booklet to identify the correct name of the second element – do not guess. Look at the second part of the name of the compound then look at your periodic table and try and find the element that matches. Example 1 Berylliumnitride contains the elements beryllium and nitrogen. Example 2 Titaniumfluoride contains the elements titanium and fluorine. Example 3 Lithiumsulfide contains the elements lithium and sulfur. Example 4 Magnesiumchloride contains the elements magnesium and chlorine

17. Naming Compounds 1Think-write-pair-compare • Work in pairs. • Individually, read the Naming 2 Element compounds help card. • You should both attempt to name each compound or identify the elements in the compound in Q1 and Q2 of the work card. Compare your answer with your partner before moving onto the next problem. • Continue to work through the rest of the compounds like this. • When you are finished your teacher will give you an answer card to check your answer.

18. Naming 3 Element Compounds The Endings –ATEor –ITEare used instead of –IDE when oxygen is present in a compound as well as 2 other elements. The ONLY exception to this rule is when an element is bonded to hydrogen and oxygen E.g. iron, hydrogen and oxygen would make a compound called iron hydroxide. Example 1 When sodium reacts with chlorine and oxygen, the compound sodiumchlorate is made. The name of the first element stays the same but the ending of the second element is changed to -ATE  Example 2 Magnesium reacts with phosphorus and oxygen to form magnesiumphosphate Example 3 Potassium reacts with carbon and oxygen to form potassiumcarbonate  Example 4 Lithium reacts with hydrogen and oxygen to form lithiumhydroxide

19. Identify the Elements from the Compound Use your Data Book The first element in the compound is easy to identify as the name is unchanged. Look at the second part of the name of the compound then look at your periodic table and try and find the element that matches. The ending –ATE or –ITE indicates the presence of oxygen as well as the other 2 elements. Example 1 Berylliumnitrate contains the elements beryllium and nitrogen and oxygen Example 2 Titaniumcarbonate contains the elements titanium and carbonand oxygen. Example 3 Lithiumsulfate contains the elements lithium and sulfur and oxygen. Example 4 Magnesiumsulphite contains the elements magnesium and sulfur and oxygen.

20. Naming Compounds 2Think-write-pair-compare • Work in pairs. • Individually, read the Naming 3 Element compounds help card. • You should both attempt to name each compound or identify the elements in the compound in Q3 and Q4 of the work card. Compare your answer with your partner before moving onto the next problem. • Continue to work through the rest of the compounds like this. • When you are finished your teacher will give you an answer card to check your answer.

21. Lesson 1c LI: Write word equations for reactionsTitle: Writing word equations Green – I can state that reactants are before the arrow in an equation and products are after the arrow. I can state that an arrow is used to indicate a chemical reaction has taken place. I can form word equations from information about chemical reactions. Amber – I can state that reactants are before the arrow in an equation and products are after the arrow. I can state that an arrow is used to indicate a chemical reaction has taken place. Red - I can state that reactants are before the arrow in an equation and products are after the arrow.

22. Writing Word Equations The chemicals we have at the start of a reaction are called reactants. When a chemical reaction takes place the atoms in these substances are rearranged to form new chemicals. The substances formed in a reaction are called products. Example If copper oxide is heated with magnesium it will react to form magnesium oxide and copper. We can write this as a simple word equation:

23. Lesson 8a Writing Word EquationsThink-write-pair-compare • Work in pairs. • Individually, read the Writing Word Equations help card. • You should both attempt each word equation individually. Compare your answer with your partner before moving onto the next problem. • Continue to work through the rest of the equations like this. • When you are finished your teacher will give you an answer card to check your answer.

24. Fast Finishers… Write the word equations for each of the following chemical reactions: 1)When dissolved beryllium chloride reacts with dissolved silver (I) nitrate in water, aqueous beryllium nitrate and silver(I) chloride powder are made. 2)When isopropanol (C3H8O) burns in oxygen, carbon dioxide, water, and heat are produced. 3)When dissolved sodium hydroxide reacts with sulfuric acid (H2SO­4), aqueous sodium sulfate, water, and heat are formed. 4)When fluorine gas is put into contact with calcium metal at high temperatures, calcium fluoride powder is created in an exothermic reaction. 5)When sodium metal reacts with iron (II) chloride solution, iron metal and sodium chloride solution are formed.

25. Fast Finishers… Answers 1)When dissolved beryllium chloride reacts with dissolved silver(I) nitrate in water, aqueous beryllium nitrate and silver(I) chloride powder are made. Beryllium chloride + silver (I) nitrate  beryllium nitrate + silver (I) chloride 2)When isopropanol (C3H8O) burns in oxygen, carbon dioxide, water, and heat are produced. Isopropanol + oxygen  carbon dioxide + water 3)When dissolved sodium hydroxide reacts with sulfuric acid solution (H2SO­4), aqueous sodium sulfate, water, and heat are formed. Sodium hydroxide + sulfuric acid  sodium sulfate + water 4)When fluorine gas is put into contact with calcium metal at high temperatures, calcium fluoride powder is created in an exothermic reaction. Fluorine + calcium  calcium fluoride 5)When sodium metal reacts with iron (II) chloride solution, iron metal and sodium chloride solution are formed. Sodium + iron(II) chloride  iron + sodium chloride

26. Lesson 1d LI: Work out chemical formulae using prefixesTitle: Chemical Formulae using prefixes Green – I can state the meaning of the prefixes mono, di, tri, etc. I can state that prefixes are used in naming compounds to indicate the number of atoms present. I can state that no prefix in part of the name indicates 1 atom. I can write formulae from the name of a compound with prefixes. I can name a compound using prefixes from the formula. Amber - I can state the meaning of the prefixes mono, di, tri, etc. I can state that prefixes are used in naming compounds to indicate the number of atoms present. I can state that no prefix in part of the name indicates 1 atom. I can write formulae from the name of a compound with prefixes. Red - I can state the meaning of the prefixes mono, di, tri, etc. I can state that prefixes are used in naming compounds to indicate the number of atoms present. I can state that no prefix in part of the name indicates 1 atom.

27. Chemical Formula • The chemical formula for a covalent compound gives the number of atoms of each element in the molecule. E.g. Water Chemical formula H2O Carbon dioxide Chemical formula CO2

28. Formulae from Prefixes

29. Example 1: Sulfur trioxide Chemical formula SO3 3 oxygen atoms 1 sulfur atom

30. Example 2: Carbon tetrachloride Chemical formula CCl4 4 chlorine atoms 1 carbon atom

31. Write the chemical formula for the following compounds: 1. Carbon monoxide 2. Boron tribromide 3. Phosphorus pentachloride 4. Dinitrogen trioxide 5. Xenon hexafluoride 1. CO 2. BBr3 3. PCl5 4. N2O3 5. XeF6 1.Carbon dioxide 2. Dinitrogen tetroxide 3. Nitrogen dioxide 4. Carbon tetrachloride 5. Sulfur dioxide Write the name of the following compounds: 1. CO2 2. N2O4 3. NO2 4. CCl4 5. SO2

32. Lesson 2 LI: Describe factors that affect rate of reactionTitle: Factors Affecting Rate of Reaction Green – I can explain why changing particle size, concentration of reactants and temperature affect the rate of a reaction. I can state that using a catalyst will also speed up the rate of a reaction. Amber – I can state all the factors that affect the rate of reaction. Red – I can state 1 factor that affects the rate of a reaction.

33. Changing the Speed of a Reaction • Reactions can be followed by measuring changes in concentration, mass and volume of reactants and products • We need to be able to describe how the following affect the rate of reaction • Particle size • Concentration • Temperature • Catalyst • We also need to give examples of reactions (both laboratory and everyday) affected by the above.

34. Rates of Reaction • Chemical reactions are taking place all around us at different speeds or rates • In the lab, we can measure the speed of a reaction by finding out how much product is made in a certain time • The speed of a reaction can be changed if we alter the conditions of the reaction

36. Practical Activity 1.1Speed of Reactions AIM: to demonstrate fast and slow reactions in the lab. Method: • Add a 2cm piece of magnesium to 5cm3 of 0.5M Hydrochloric acid in a test tube. • Burn a 2cm piece of magnesium in a Bunsen burner. • Add a lump of zinc to 5cm3 of copper sulfate in a test tube. • Add an iron nail to 5cm3 of 0.1M hydrochloric acid. • Add around 3cm3 of barium chloride to 3cm3 of 0.1M sulfuric acid in a test tube. If there appears to be no reaction, leave the test tube of reactants set up and observe them again next day. • Your teacher will demonstrate the reaction between sucrose and concentrated sulfuric acid (fume hood). • Your teacher will demonstrate the reaction between glycerol and potassium permanganate.

37. Results: Write a conclusion placing the reactions in order from fastest to slowest reaction rate. Conclusion:

38. Downward Displacement of Water • When chalk (calcium carbonate) is added to acid, one of the products is carbon dioxide gas • The gas can be collected using an upside down measuring cylinder filled with water. • The data collected during the experiment can be used to find out more about the rate of the reaction • Your teacher may demonstrate this experiment.

39. Practical Activity 1.2 Downward Displacement of Water AIM: to demonstrate downward displacement of water Method: • The experiment is carried out twice: 1. with 0.5 g of chalk lumps 2. with 0.5 g of chalk powder • In both experiments 10 ml of acid is used. • Ensure the mass of chalk and volume of acid is measured correctly • The gas volume is recorded every 30 secs until 10 mins or the reaction is complete. • Ensure test tube remains in test tube rack throughout experiment.

40. Downward Displacement of Water The gas produced was collected in the measuring cylinder and the volume recorded every 30 seconds carbon dioxide gas 10 ml acid + 0.5 g chalk lumps Draw in techniques jotter

41. Results: Your Task: Process the data in table into a line graph. Write a conclusion stating which reaction was faster, with lumps of with powder? Conclusion:

42. Title • Points must be plotted correctly • Points joined together correctly. • Axis drawn using a ruler. Appropriate scale and label with units Appropriate scale and label with units

43. Experiment A Experiment B The experiment using powder is a faster reaction than with lumps.

44. Graphs Following Reactions • The faster the reaction, the steeper the slope of the graph. • If an equal mass of chalk was used in each experiment, the final volume of gas should be the same.

45. Changing the Rate of a Reaction • The rate of a reaction will increase if we: • DECREASE the particle size (increase the surface area) • INCREASE the temperature • INCREASE the concentration • USE A CATALYST to lower the energy required for the reaction to occur.

46. Lesson 1 Factors Affecting Rate of ReactionStand and Deliver • Work in groups of 4, number yourselves 1, 2, 3 and 4. • You will each be given an information card about changing the rate of a reaction • Surface area • Concentration • Temperature • Catalyst • To begin, number 1’s should work with another number 1, 2’s with other 2’s and so on. • Read over card and make a summary in your notes. Compare your notes with the others and make any changes. • Return to your original group and then take it in turns to explain your card to the group. Number 1’s will go first, then 2 then 3 then 4. • Write a summary in your notes for the other ways of changing the speed of a reaction. • Complete the card sort in pairs to test your knowledge.

47. Surface Area When particle size is decreased, the surface area is increased. This means more of a substance is able to react and so the rate of reaction will increase. Low surface area High surface area 6 sides 12 sides 24 sides Faster reaction Slower reaction In the reaction between acid and marble chips (calcium carbonate), the reaction occurs faster when powder is used instead of lumps. More of the calcium carbonate particle are exposed to the acid particles so they can collide and react together. Everyday example: Sticks burn faster than logs, smaller cut vegetables cook faster than larger cut ones.

48. Concentration The concentration of a solution is the mass of a substance dissolved in a known volume of water. The units are g/litre or moles/litre Dilute solution: not a lot of particles dissolved in the water Concentrated Solution: a lot of particles dissolved in the water 0.1 mol/l 1.0 mol/l Slower reaction Faster reaction The more particles of a reactant there are, the more likely they the reactants are to bump into each other. If they collide correctly they will react so they rate of reaction is increased by increasing the concentration of the reactants. E.g magnesium metal and acid react to form water and hydrogen gas. Everyday example: Concentrated bleach removes stains faster than dilute bleach.

49. Temperature When the temperature of the reactants is increased the particles gain energy and they move more quickly. If particles are moving around more they are more likely to collide with each other. If the reactant particles collide correctly they will react and so the rate of the reaction will increase. Slower reaction Faster reaction Lower temperature: particles not moving much so only a few collisions and reaction is slow Higher temperature: particles moving much faster so more collisions so reaction is fast. Everyday example: Milk goes sour faster at room temperature than in a fridge In the reaction between a metal and an acid, hydrogen gas is produced. The gas is produced faster when the reaction is warm.

50. Catalyst Catalysts are substances that are added to chemical reactions to increase the rate at which the reaction occurs. They do this by lowering the amount of energy required to make the reaction occur (the activation energy). Molecules of one or both reactants form bonds with the surface of the catalyst. This then weakens the bonds within the reactant molecule. Molecules react on the catalyst surface (the active site) The angle of collision is likely to be favourable since one of the molecules is fixed. The product molecules then leave the catalyst and the vacant site can be occupied by another reactant molecule. Everyday example: Catalysts are used in car exhaust systems to convert poisonous gases like carbon monoxide to less harmful carbon dioxide.