2. Starter: Why are symbols known as a universal language?

3. irritant

4. harmful

5. flammable

6. corrosive

7. toxic

8. oxidising

9. explosive

10. radiation

11. Continuous and batch production. Continuous Batch

12. Continuous process. This process continues for 24 hours a day. The plant only shuts down for maintenance. Used to produce high volume, high demand, bulk chemicals eg. ammonia. Examples of other continuous processes include, fractional distillation, cracking.

13. Batch process. Measured amounts of raw materials are mixed and processed to make the product. Smaller quantities are produced. Only produced when there is a demand. Used to make speciality or fine chemicals eg. pharmaceutical drugs.

14. Comparing the 2 processes. Cost: Much lower for continuous process - bulk chemicals, higher volume, more efficient energy costs, more automation, lower raw material costs. Quality/purity: Much higher for batch process - fine chemicals, greater control, higher quality raw materials, more testing.

15. pH scale. The pH scale tells us how acidic or alkaline a solution is. It is used to measure and help control the pH in a range of industries. industries.

16. pH scale

18. Important acids. Hydrochloric acid – HCl (aq) Nitric acid– HNO 3(aq) Sulfuric acid – H 2 SO 4(aq) Make sure you learn and remember them! What does the (aq) mean?

19. Acidic compounds in different states. Acids that are solids – citric and tartaric. Acids that are liquids – nitric, sulfuric and ethanoic. Acids that are gases – hydrogen chloride.

20. Formula of some alkalis. Sodium hydroxide – NaOH Potassium hydroxide – KOH Magnesium hydroxide – Mg(OH) 2 Learn and remember these!

21. What is an acid? All acids contain hydrogen atoms. When acids dissolve in water they produce hydrogen ions, H +. HCl(g)  H + (aq) + Cl - (aq) That is why acids only behave like acids when they are dissolved in water.

22. What about alkalis? The same can be applied to alkalis. This time it is the presence of the OH - ion that makes a substance an alkali. Strong alkalis like NaOH sodium hydroxide split up completely. NaOH(aq)  Na + (aq) + OH - (aq)

23. What happens to the ions during neutralisation.

24. Ionic equations The reaction between acids and alkalis can be represented by the following equation: Acid and alkali H + (aq) + OH - (aq)  H 2 O (l) Note that water is produced.

25. Neutralisation – Hydrochloric acid Neutralisation

26. Neutralisation – Sulphuric acid Neutralisation

27. Neutralisation – Nitric acid Neutralisation

28. Strong acid/base titration. This is the shape of the curve when a strong acid is reacted with a strong base. What do you notice about the shape?

29. Reactions of metals with acids Copy and complete the following reactions: 1)Calcium + hydrochloric acid 2)Zinc + hydrochloric acid 3)Iron + hydrochloric acid 4)Lithium + sulphuric acid METAL + ACID SALT + HYDROGEN e.g. magnesium + hydrochloric acid magnesium chloride + hydrogen Mg H Cl Mg Cl H H H

30. Reactions of metal oxides with acid A metal oxide is a compound containing a metal and oxide. They are sometimes called BASES. For example: Mg O Na O O Al O O Magnesium oxide Sodium oxide Aluminium oxide METAL OXIDE + ACID SALT + WATER Copy and complete the following reactions: 1)Magnesium oxide + hydrochloric acid 2)Calcium oxide + hydrochloric acid 3)Sodium oxide + sulphuric acid Mg O H Cl Mg Cl H H O H

31. Acid alkali reactions A neutralisation reaction occurs when an acid reacts with an alkali. An alkali is a metal oxide or metal hydroxide dissolved in water. ACID + ALKALI SALT + WATER Na Cl H H O H Na O H Copy and complete the following reactions: 1)Sodium hydroxide + hydrochloric acid 2)Calcium hydroxide + hydrochloric acid 3)Sodium hydroxide + sulphuric acid 4)Magnesium hydroxide + sulphuric acid

32. Reactions of metals carbonates with acid A metal carbonate is a compound containing a metal, carbon and oxygen. METAL CARBONATE + ACID SALT + CARBON DIOXIDE + WATER Copy and complete the following reactions: 1)Magnesium carbonate + hydrochloric acid 2)Calcium carbonate + hydrochloric acid 3)Sodium carbonate + sulphuric acid Mg H Cl Mg Cl H H H C O O O O O O C

33. Exothermic & Endothermic

34. During a chemical reaction there is an energy transfer. Combustion of methane in a Bunsen burner 34 Explain Two things happen to bonds. reactantsproducts methane oxygen carbon dioxide water

35. The atoms in the reactants are held together by chemical bonds. Chemical energy 35 Explain Low energy High energy

36. 36 Explain Bonds break Heat energy from a match breaks the bonds and splits the atoms apart A small amount of energy from a match. Chemical energy Low energy High energy 1

37. Atoms join to make products. As new bonds form, energy is released. 37 Bonds are made Explain A lot of energy is released. Chemical energy Low energy High energy 2

38. Exothermic reactions

39. 39 Explain An energy level diagram for an exothermic reaction. SS3 energy products reactants exothermic

40. 40 Explain In an exothermic reaction, the reactants contain more energy than the products. I get it. HEAT OUT! The left-over energy is released as heat.

41. Exothermic reactions

42. Endothermic reactions

44. 44 Explain An energy level diagram for an endothermic reaction. The products contain more energy than the reactants. This extra energy comes from the surroundings. energy reactants products endothermic

45. In an exothermic reaction more energy is released making new bonds than is taken in breaking bonds. There is heating. It’s all ‘ Make and Break ’! In an endothermic reaction less energy is released making new bonds than is taken in breaking bonds. There is cooling.

46. Bond energies The energy needed to break a chemical bond Different chemical bonds have different bond energies Chemical bondBond energy, kJ/mole H―H436 O=O498 O―H464

47. Working out ∆H Draw an energy level diagram with all the reactants and products on it energy course of reaction 2H 2 + O 2 2H 2 O

48. Working out ∆H Show all the bonds in the reactants energy course of reaction 2H 2 O H―H O=O+

49. Working out ∆H Show all the bonds in the products energy course of reaction H―H O=O+ HH O HH O

50. Working out ∆H Show the bond energies for all the bonds energy course of reaction 436 O=O+ HH O HH O

51. Working out ∆H Show the bond energies for all the bonds energy course of reaction 436 498+ HH O HH O

52. Working out ∆H Show the bond energies for all the bonds energy course of reaction 436 498+ HH O 464 +

53. Working out ∆H Show the bond energies for all the bonds energy course of reaction 436 498+ 464 + +

54. Working out ∆H Add the reactants’ bond energies together energy course of reaction 464 + + 1370

55. Working out ∆H Add the products’ bond energies together energy course of reaction 1370 1856

56. Working out ∆H ∆H = energy in ― energy out energy course of reaction 1370 1856 1370 1856 ―

57. Working out ∆H ∆H = energy in ― energy out energy course of reaction 1370 1856 1370 1856 -486 ―

58. Working out ∆H ∆H = energy in ― energy out energy course of reaction 1370 1856 ∆H = -486

59. Working out ∆H Summary The energy values have units of kJ/mole In the exam, you will be given the energy values and all the bonds to make or break ∆H is energy in – energy out Energy goes in to break bonds Energy goes out when bonds are made

60. Why do new medicines need to be developed? developed?

61. What are the stages in a chemical synthesis? 1. Separate product from reaction mixture. 2. Work out quantities of reactants needed. 3. Purify the product. 4. Risk assessment. 5. Choose suitable equipment and reaction conditions. 6. Measure yield and check purity. 7. Choose the reaction or series of reactions.

62. Experimental techniques. 1. Dissolving – helps the reactants to mix and therefore react easier. 2. Filtration – separates product from the rest of the reaction mixture. 3. Evaporation – removes the excess water. 4. Crystallisation – the solid product is formed from a saturated solution. 5. Drying – removes any remaining water.

63. Pure. Only contains one substance. Free from contaminants. Is the water opposite really pure?

64. Both are salt are they the same purity? Rock saltTable salt

65. Grades of purity. Purifying a chemical is done in stages. The higher the purity the more expensive it becomes. Manufacturers only buy the quality most suitable for their purpose. Both contain limestone, which will be most pure?

66. Deciding the grade of chemical. 1. The amount of impurities. 2. What the impurities are. 3. How they can affect the process. 4. Whether they will end up in the product, and whether it matters if they do.

67. Checking purity. There are various methods of checking purity; 1. Melting points. 2. Spectroscopic techniques. 3. Chromatography. 4. Titration.

68. Titration Step 1. Fill the burette with a solution of acid or alkali of known concentration.

69. Titration Step 2. Weigh out accurately the sample that you want to test the purity.

70. Titration Step 3 Dissolve the substance in pure water. Add a few drops of indicator.

71. Titration Step 4. Add alkali/acid from the burette to the solution. Swirl the contents during each addition. Near the end point (when the indicator changes colour) add the alkali/acid drop by drop.

72. Relative formula mass

73. Percentage yield. To calculate the percentage yield use the following formula: Percentage yield = actual yield x 100 theoretical yield Theoretical yield – is the maximum mass of product that could be made. Actual yield – is the mass of product collected.

74. Calculating percentage yield. In an experiment 32g of CO 2 are produced, the theoretical yield was 40g. Calculate the percentage yield. Tip – the answer must always be less than 100%. If it is more than 100% then you have got the calculation the wrong way round.

75. How did you do? Percentage yield = actual yield x 100 theoretical yield Percentage yield = 32 x 100 40 = 75% Don’t forget the units! Answer question 3 p.225 Additional textbook.

76. Percentage yield Some example questions: 1)The theoretical yield of an experiment to make salt was 10g. If 7g was made what is the percentage yield? 2)Dave is trying to make water. If he predicts to make 15g but only makes 2g what is the percentage yield? 3)Sarah performs an experiment and has a percentage yield of 30%. If she made 50g what was she predicted to make? Percentage yield = Actual yield Theoretical yield X 100%

77. Balancing equations

78. Calculating the masses of reactants and products. Step 1 – Write a balanced symbol equation. Step 2 – Calculate the RFM for each reactant and product. Step 3 – Work out ratio for each reactant and product.

79. Ratios. If 1 loaf of bread can make 15 sandwiches. How many sandwiches would; a) 2 loaves make? b) 6 loaves make? c) 1/3 of a loaf make? Practise ratios here.here

80. Calculating the mass of a product E.g. what mass of magnesium oxide is produced when 60g of magnesium is burned in air? Step 1: READ the equation: 2Mg + O 2 2MgO IGNORE the oxygen in step 2 – the question doesn’t ask for it Step 3: LEARN and APPLY the following 3 points: 1)48g of Mg makes 80g of MgO 2)1g of Mg makes 80/48 = 1.66g of MgO 3)60g of Mg makes 1.66 x 60 = 100g of MgO Step 2: WORK OUT the relative formula masses (M r ): 2Mg = 2 x 24 = 48 2MgO = 2 x (24+16) = 80

81. Work out M r : 2H 2 O = 2 x ((2x1)+16) = 36 2H 2 = 2x2 = 4 1.36g of water produces 4g of hydrogen 2.So 1g of water produces 4/36 = 0.11g of hydrogen 3.6g of water will produce (4/36) x 6 = 0.66g of hydrogen M r : 2Ca = 2x40 = 80 2CaO = 2 x (40+16) = 112 80g produces 112g so 10g produces (112/80) x 10 = 14g of CaO M r : 2Al 2 O 3 = 2x((2x27)+(3x16)) = 204 4Al = 4x27 = 108 204g produces 108g so 100g produces (108/204) x 100 = 52.9g of Al 2 O 3 1)When water is electrolysed it breaks down into hydrogen and oxygen: 2H 2 O 2H 2 + O 2 What mass of hydrogen is produced by the electrolysis of 6g of water? 3) What mass of aluminium is produced from 100g of aluminium oxide? 2Al 2 O 3 4Al + 3O 2 2) What mass of calcium oxide is produced when 10g of calcium burns? 2Ca + O 2 2CaO

82. Calculations from Equations Calculations from equations

83. Calculations from Equations Calculations from equations

84. Reaction was slow at the start and then speeded up Reaction was fast at the start then slowed down. Rate of reaction remained constant throughout the experiment. Time (s) Volume of gas produced (ml) 1.Draw rate graphs for each scenario (use axis given) 2.Which graph would you expect to see for a rates of reaction experiment? 3.How would you calculate the rate of the reaction?

85. What can you measure? You can either measure; 1. The amount of product formed or, 2. The amount of reactant used up. This is the dependent variable. What is the independent variable? Time.

86. The three methods. 1. Volume of gas produced. 2. Change in mass. 3. Precipitate formed – a precipitate is an insoluble solid.

87. Volume of gas produced.

88. Loss of mass. Why is there a loss of mass? A gas is being produced.

89. Precipitate formed. As the reaction proceeds more precipitate is formed and the solution becomes cloudier until the cross cannot be seen. This reaction is known as the disappearing cross experiment.

90. Interpreting graphs 1.When is the reaction fastest? 2. When does the reaction slow down? 3. From the graph how do you know the reaction has stopped? 4. At what time does the reaction stop? 5. What volume of gas is produced?

91. Fast or slow? Rate is a measure of how fast the reaction goes or the speed of the reaction. Fast reactions have high rates. They are over quickly – within a few seconds. Slow reactions have low rates. They take longer – a few minutes up to years.

92. Can you give examples of fast and slow reactions? Fast reactions: Explosions. Match burning. Slow reactions: Rusting/corrosion. Concrete setting. Cooking.

93. What must happen for a reaction to take place? Reactions take place when particles collide. Not all collisions are successful. Particles must collide with enough energy for a successful collision. This is called the Collision Theory.Theory.

94. It also depends upon how they collide as well!

95. So how do you speed up a reaction? Quite simply by increasing the frequency (how often) of successful collisions. How can you increase the frequency of successful collisions? What factors did we investigate last lesson?

96. FactorsFactors that affect the rate of a reaction. The factors are: 1. Temperature. 2. Concentration. 3. Surface area. 4. Catalyst.

97. Temperature. Increasing the temperature increases the energy of the particle, which means; 1. The particles collide more often. 2. There will be more successful collisions.

98. Concentration. Increasing the concentration increases the rate of a reaction. Increasing the concentration means there are more particles in the same space and so the particles will collide more often. High concentration. Low concentration

99. Surface Area. Increasing the surface area, increases the rate of reaction. The bigger the surface area, the more often the particles will collide.

100. Catalyst. A catalyst is a substance that speeds up a chemical reaction. The energy needed to start a reaction is called its activation energy. A catalyst lowers the activation energy.