Chemistry Experiment Reports

Transcription

1 Name Surname Chemistry Experiment Reports GJ Zahra, B.Ed (Hons) Year Experiment Number Section Title Mark 1A n/a Diffusion /15 1B n/a Rate of Diffusion /15 2 A Distillation /15 3 A Paper Chromatography /15 4 A Separating Salt and Sand* /30 5 C Preparation and test for Hydrogen /15 6 C Preparation and test for Oxygen /15 7 n/a Rusting of Iron /15 8 n/a Metallic and Non-Metallic Oxides n/a 9 n/a Hard and Soft Water /15 10 n/a Calculating the formula of hydrated salts /15 11 n/a Indicators and ph /15 12 D Preparation of Copper (II) Sulfate /15 13 D Preparation of Copper (II) Hydroxide* /30 14 B Electrolysis of Copper (II) Sulfate /15 15 E The Reaction of Metals with Acids /15 16 E Metal Displacement Reactions /15 17 B Action of Heat on Materials /15 18 J Qualitative Analysis 1 /15 19 J Qualitative Analysis 2* /30 20 n/a Preparing a Standard Solution n/a 21 I Titration /15 22 F The Halogens /15 23 C Preparation and Properties of SO 2 /15 24 C Preparation and Properties of Ammonia /15

2 Name Surname Chemistry Experiment Reports GJ Zahra, B.Ed (Hons) Year Experiment Number Section Title Mark 25 H The effect of temperature on the rate of reaction (HCl + CaCO 3 ) /15 26 H Factors affecting the ripening of bananas* /30 27 G Estimating the heat of combustion of an alcohol /15 28 G Determining the heat of neutralization /15 29 I Calculating the percentage of calcium carbonate in egg-shells* /15

3 Experiment 1A Title: DIFFUSION Aim To investigate the rate of diffusion in the three states of matter Apparatus Diagram Air freshener, food colouring, beakers, rice, marbles, teat pipette Draw a labelled diagram for the experiment in a sharp HB pencil Method With one person standing at an edge of the room, spray some air freshener in the air. Notice whether or not the air freshener spreads through the room. Pour about 100cm 3 of tap water in a beaker. Using a pipette, slowly place some (about ten) drops of food colouring on the water surface. Allow the mixture to stand. In a beaker place some rice. On the rice place some marbles. Allow the mixture to stand. Did the air freshener spread throughout the room? How do you know? Did the food colouring spread throughout the water in the beaker? Did the marbles spread throughout the rice? Which process happened the fastest? Precautions Were the mixtures stirred or agitated? Why? A teat pipette was used to add the food colouring. Why? Define diffusion. Diffusion can only occur in and. This is because the particles in gases and liquids ( ) while the particles in solids ( ). Diffusion happens fastest in because the particles can ( ). Important Notes for your first lab report Lab reports carry a total of 15% of your SEC examination mark. Diagrams should never be shaded, except for corks or rubber bungs (neat, diagonal lines). Diagrams should be neat, of an appropriate size, drawn in a sharp HB pencil and fully labelled. Lines used for labelling diagrams should not have any arrow heads. Such an arrow means heat. The method should be written in past passive voice. The discussion and conclusion should be in paragraph form. Do not just answer the questions in short.

4 Experiment 1B Title: RATE OF DIFFUSION Aim To see which of two gases, ammonia (NH 3 ) or hydrogen chloride (HCl), is the heaviest by observing their rate of diffusion Apparatus Glass tube, ammonia solution, hydrochloric acid, cotton wool, retort stand with clamp, latex gloves Diagram Method Gently attach the glass tube with the clamp and retort stand in a horizontal position Soak one cotton wool in ammonia solid and the other in hydrochloric acid (caution: wear gloves) Place the soaked cotton wools at different ends of the tube What happened after some time? Where did the solid form (i.e. closer to the ammonia or to the hydrogen chloride). Precautions The cotton wool pieces were placed at their respective ends in the same time so that ( ) What are the safety signs for ammonia solution? What are the safety signs for hydrochloric acid solution? The white solid was ammonium chloride which formed where the hydrogen chloride and ammonia met and reacted. NH 3(g) + HCl (g) > NH 4 Cl (s) Since the solid formed closer to the side containing, the experiment showed that is heavier than. This is because heavy particles diffuse ( ). In fact, the relative mass of ammonia is given in data books as 17 while the relative mass of hydrogen chloride is given as 36.5.

5 Experiment 2 Title: DISTILLATION Aim To obtain water from its solution with copper(ii) sulfate Apparatus Take note of the apparatus used Diagram Draw your own diagram Method Set up the apparatus as shown in your diagram Add anti-bumping granules to the solution Light the Bunsen burner and heat the mixture with a blue Bunsen flame What colour changes did you note? What was the temperature reading when the distillate started being collected? Precautions Why were anti-bumping granules used? How was the Bunsen burner lit up? What are the hazard signs for copper (II) sulfate? Distillation is used to separate ( ) Why is the water set to flow from the bottom to the top of the condenser? Use the internet or your text book to find industrial applications of distillation or fractional distillation. In Malta, water is purified by reverse osmosis rather than by distillation. This is because ( ) [use the link below or any other source of information to discuss the advantages of reverse osmosis over distillation

6 Experiment 3 Title: PAPER CHROMATOGRAPHY Aim To separate and compare the coloured components making up different blue inks and colourings Apparatus Take note of the apparatus used including the brand of the food colouring Diagram Use your notes to draw your own diagram. Method Write your own method. Use points such as This was repeated using alcohol as a solvent to reduce the volume of writing. Attach your chromatogram or a diagram/photo of them Precautions Why was a pencil used to write/mark the chromatograms? How was the food colouring transferred to the chromatogram? Why? Find the hazard signs for alcohol (ethanol). Chromatography is used to separate ( ) According to this experiment, which are the constituent colours of the different blue inks? Which inks are not soluble, or soluble in only one solvent? Which inks are made up of more than one colour? Which of these is the most soluble? How do you know this? Where there any differences between the products (food colouring / inks) used by the different brands or for different purposes (i.e. compare different markers, pens, or food colourings)? Use the internet or your text book to find applications of chromatography.

7 Experiment 4 Title: INVESTIGATION: SEPARATING SALT, SAND AND AMMONIUM CHLORIDE Group Members Problem To obtain table salt (sodium chloride) from its mixture with sand and ammonium chloride Plan Apparatus (plan) Diagram (plan) Teacher s Notes and Signature

8 Experiment 4 Title: INVESTIGATION: SEPARATING SALT,SAND, AND AMMONIUM CHLORIDE Apparatus Take note of the apparatus you really used Diagram Only draw a diagram if your suggested diagram was not of the setup used Method Write what was done in the experiment. You simply change sentences from the plan to the past passive voice while adding sentences or phrases to account for any changes. What was the appearance of the mixture and that of the separated solids? Where there any hints of impurities in the appearance of the solids? Why did you choose these separating techniques? What is each technique used for? How was the sand removed from the mixture? How was the salt obtained? Evaluation What were the changes made to your original plan? Was any of the apparatus you asked for replaced with something else? What were the advantages and/or disadvantages of this? How much of the mixture was used and why? If you added any other chemicals, how much of these chemicals were added and why? What were the safety measures taken during the experiment? What are the hazard symbols of the used chemicals.

9 Experiment 5 Title: PREPARATION AND TEST FOR HYDROGEN Aim To prepare hydrogen To test for hydrogen Apparatus Take note of the apparatus and chemicals used. Diagram Draw your own diagram. Remember that this is a test tube preparation and not collection over water as in your notes! Method Place a small piece (1-2cm) of magnesium ribbon in a test tube Place one pipette of acid in another test tube Collect a small sample of the acid with a stirrer and place it on red litmus paper. Repeat for blue litmus paper Mix the acid with the metal Touch the bottom of the test tube to see whether the reaction is producing heat or absorbing heat Close the mouth of the test tube using a thumb Place a burning splint at the mouth of the test tube and remove the thumb Collect a small sample of the liquid in the test tube with a stirrer and place it on red litmus paper. Repeat for blue litmus paper What was the effect of the acid on red and blue litmus? What was the effect of the final solution on red and blue litmus? What was observed when the acid was added to the magnesium? Did the reaction produce or absorb heat? Did the gas evolve have a colour or smell? What happened when the gas came in contact with the burning splint? Precautions Look up the hazard warnings for each chemical used. To where was the test tube pointed during the reaction? What about the quantities and concentration of chemicals used? What is the general reaction by which hydrogen is prepared? Write a balanced chemical equation for the process. Hydrogen buns with a pop to produce. The chemical equation is (write down the equation for the combustion of hydrogen). How could the hydrogen prepared be collected? Give some uses of hydrogen. What do the colour changes of the litmus papers show about the acidity of the liquid before and after the reaction?

10 Experiment 6 Title: PREPARATION AND TEST FOR OXYGEN Apparatus Aim To prepare oxygen To test for oxygen Diagram Draw your own diagrams. Remember that this is a test tube preparation and not collection over water as in your notes! Method Place a small amount of manganese (IV) oxide in a test tube Using a pipette, slowly add a small amount of hydrogen peroxide Make observations about the colour and smell of the gas produced Touch the bottom of the test tube to see whether the reaction is producing heat or absorbing it Close the mouth of the test tube using a thumb Place a glowing splint at the mouth of the test tube and remove the thumb Close the mouth of the test tube again, place a burning splint and remove the thumb Set up the apparatus for filtration and filter the mixture What was observed when the substances were mixed? Did the reaction produce or absorb heat? Did the gas evolve have a colour or smell? What happened when the gas came in contact with the glowing splint? What happened when the gas came in contact with the burning splint? Precautions Look up the hazard warnings for each chemical used. To where was the test tube pointed during the reaction? What about the quantities and concentration of chemicals used? Write and explain a balanced chemical equation for the process. What is the role of manganese (IV) oxide in this process? How do you know that it is not a reactant? What is the chemical test for oxygen? How could the oxygen prepared be collected? Give some uses of oxygen.

11 Experiment 7 Title: RUSTING OF IRON Aim To see how water, air and salt affect rusting To assess which conditions are essential for rusting Apparatus Iron nails, calcium chloride (desiccant), oil, sodium chloride, test tubes, rubber bung, Bunsen burner, beaker. Diagram Using the apparatus above, complete the diagrams so that the test tubes contain what is listed in the table of results only Method Set up the apparatus as shown in the diagram Explain the use of calcium chloride, oil, boiling water and the stoppers. Let the apparatus to stand for a week Precautions Write down any precautions used, including hazards for the materials used. Which are the conditions essential for rusting? Write a chemical equation. Is salt essential for rusting? What is the role of salt in the rusting of iron?

12 Experiment 8 Title: METALLIC AND NONMETALLIC OXIDES Aim To prepare different oxides by heating the elements in air To test whether a number of oxides are acidic or basic (acid neutralizers) Apparatus Straw, universal indicator, pipette, beaker, crucible with lid, clay triangle combustion spoon, gas jar, sulfur, magnesium, copper, dilute HCl OXIDE 1: CARBON DIOXIDE Method Place a small amount of distilled water in a beaker and Add one or two drops of universal indicator Note the colour change and ph of the water Using a straw, exhale carbon dioxide through the water Note the colour change and ph of the solution When the universal indicator was added to water, it changed to colour. This shows that he ph of distilled water was. Carbon dioxide is a oxide. When bubbled through water, the universal indicator changed to showing a ph of. Therefore, carbon dioxide is an oxide. OXIDE 2: SULFUR DIOXIDE Method Place a small amount of distilled water in a gas jar and Add one or two drops of universal indicator Place some sulfur on a combustion spoon with lid Burn the sulfur on a blue Bunsen flame Place the spoon with burning sulfur in the gas jar Sulfur burns with a blue flame according to the equation: Sulfur dioxide is a oxide. When dissolved in water, the universal indicator changed to showing a ph of. Therefore, sulfur dioxide is an oxide. Both sulfur dioxide and carbon dioxide are covalent oxides. This experiment showed that covalent oxides tend to be gases.

13 Experiment 8 Title: METALLIC AND NONMETALLIC OXIDES OXIDE 3: MAGNESIUM OXIDE Method Place a small amount of magnesium in a crucible and Place the crucible on a clay triangle and heat on a blue Bunsen flame until the magnesium catches fire. Stop heating at this point. Place a small amount of dilute hydrochloric acid in a beaker. Add one or two drops of universal indicator Use a spatula to transfer the magnesium oxide prepared to the beaker containing the acid and note the colour change. Magnesium burns in air with a bright white flame according to the equation: Magnesium is an oxide. When added to an acidic solution, the solution was. This shows that magnesium oxide is. The reaction between magnesium oxide and hydrochloric acid is as follows: OXIDE 4: COPPER (II) OXIDE Method Repeat the same steps above using copper instead of magnesium. and Copper reacts with oxygen according to the equation: Copper is an oxide. When added to an acidic solution, the solution was. This shows that copper (II) oxide is. The reaction between copper (II) oxide and hydrochloric acid is as follows: Both magnesium oxide and copper (II) oxide are ionic oxides. This experiment showed that ionic oxides tend to be solids.

14 Experiment 9 Title: WATER HARDNESS Aim To see the differences between hard water and soft water Apparatus Take note of the apparatus and chemicals used. Diagram Draw your own diagram. Method Set up the apparatus for evaporation as shown in the diagram Measure 30cm 3 of tap water and evaporate to dryness Measure 30cm 3 of distilled water and evaporate to dryness Put some tap water in a test tube Add some soap solution and mix well Repeat for distilled water and compare the results Put some tap water in a long test tube Add a spatula of sodium carbonate Add some soap solution and mix well Boil some tap water and let it cool down again Add some soap solution and mix well Take note of ALL your observations. You can use a table to compare the level of lathering in different cases. Precautions Include precautions that were adopted to ensure safety and fair testing (Refer to notes p. 9-10) What is hard water? When hard water was evaporated it left a solid behind. This solid was probably mainly composed of Why does hard water not lather easily with soap? Include a balanced chemical equation for the reaction of calcium sulfate with sodium stearate. What happened when sodium carbonate was added to hard water? Include a balanced chemical equation for the reaction of hard water with sodium carbonate. What happened when soap was added to boiled hard water? Why? Include a balanced chemical equation for the removal of temporary hardness. Suggest ways by which water hardness can be decreased or removed. Use these methods to explain the difference between temporary and permanent hardness

15 Experiment 10 Title: CALCULATING THE FORMULA OF HYDRATED SALTS Aim To find the formula of two hydrated salts Apparatus Take note of the apparatus and chemicals used. Diagram Draw your own diagram. Method Weigh a clean dry crucible Place some magnesium sulfate in the crucible and weigh it Heat the crucible for some time Let the crucible cool down and weigh it Repeat the previous two steps until no further change in mass is noticed Repeat the above procedure for sodium carbonate Salt Magnesium sulfate Sodium carbonate Mass of crucible Mass of crucible with hydrated salt Mass of hydrated salt Mass of crucible with anhydrous salt Mass of anhydrous salt Mass of water lost Precautions Write down any precautions used for a safe and reliable experiment. Include hazard signs for chemicals. Why was the heating and weighing of the crucible with the anhydrous salt repeated a number of times? Use well structured calculations to calculate the formula of the hydrated salts.

16 Experiment 11 Title: INDICATORS AND ph Aim To check the acid/base properties of some compounds found at home The note the colour changes of various indicators Apparatus Take note of the apparatus Diagram Draw a simple diagram showing test tubes with different substances under test Method Write down your own method for both parts of the experiment. Remember to use phrases such as This was repeated for the other compounds/indicators to shorten the method. Fill in a table of this sort for the first part of the experiment: Substance tested Colour of Litmus Nature Colour of universal indicator ph Fill in a table of this sort for the second part of the experiment Indicator Colour in Acid Colour in Alkali Precautions Write down any precautions used, including hazards of materials. The colours of the solutions with universal indicator were observed against a white ( ) Comment on the acidity/basicity of substances used at home. If possible explain why the compounds have that particular ph. What is the difference between an indicator and universal indicator? What are the advantages of a ph meter over universal indicator? Why was activated charcoal used? Define the term acid and alkali (p.4). Why does Ethanoic acid have higher ph than hydrochloric acid? What makes Ethanoic acid a weak acid? (p.6)

17 Experiment 12 Title: PREPARATION OF COPPER(II) SULFATE Aim To prepare copper(ii) sulfate To collect pure copper(ii) sulfate crystals Apparatus Take note of the apparatus used. Diagram Draw diagrams for the separation techniques used. Method Put two spatula of copper(ii) carbonate in a beaker To these add dilute sulfuric acid Make sure that not all the copper(ii) carbonate reacts Set up the apparatus for filtration as shown in the diagram Filter the mixture Set up the apparatus for recrystallization as shown in your diagram Start to evaporate the filtrate until a very concentrated solution is formed and crystals start to form Turn off the Bunsen burner and allow the crystals to crystallize What colour was the starting compound? What was observed when the substances were mixed? Comment on the appearance of copper(ii) sulfate. Precautions Look up the hazard warnings for each chemical used. Comment on the concentration of the acid used. Write a balanced equation for the reaction. What was the gas evolved? Why was an excess of copper(ii) carbonate used? Research some uses of copper(ii) carbonate.

18 Experiment 13 Title: INVESTIGATION: PREPARATION OF COPPER (II) HYDROXIDE Apparatus Take note of the apparatus you really used. Diagram Only draw a diagram if your suggested diagram was not of the setup used. Method Write what was done in the experiment. You simply change sentences from the plan to the past passive voice while adding sentences or phrases to account for any changes. What was the appearance of the reactants? What happened on mixing the reactants together? What was the appearance of the product? Why was this method of preparing and collecting copper (II) hydroxide chosen? Write a balanced chemical equation for the reaction taking place. What was the appearance of the filtrate? Thus, which reagent was in excess? Why? Evaluation What were the changes made to your original plan (if any)? Was any of the apparatus you asked for replaced with something else? Was any additional apparatus not mentioned in the original plan used? What were the advantages and/or disadvantages of this? What are the hazard symbols of the chemicals used? What were the safety measures taken during the experiment? How much of the chemicals was used and why? Is volume an accurate measure of the amount of substance used?

19 Experiment 14 Title: ELECTROLYSIS OF AQUEOUS COPPER (II) SULFATE Aim To electrolyze a solution of copper (II) sulfate. To electroplate a given object with copper. Apparatus Take note of the apparatus used. Diagram Draw diagrams for the apparatus used. Method Set up the apparatus for the electrolysis of aqueous copper (II) sulfate using a brass coin as the cathode. Insert the anode in an inverted test tube filled with water. Switch on the circuit. Take note of any observations. Record the current passing through the solution. After fifteen minutes switch off the power supply. Insert a glowing splint in the inverted test tube. Disconnect the circuit and weigh the dry cathode. What was observed at each electrode? How did the gas behave in the presence of a glowing splint? Where there any changes in the appearance of the solution? What was the current passing through the solution? What was the mass of the cathode before and after the experiment? Precautions Look up the hazard warnings for each chemical used. Why was a relatively small current used? Write ionic half equations for the reactions taking place at each electrode. What happened at each electrode? Which ions were reduced and oxidized? What were the products at each electrode? How do you know? What was the total charge that was passed through the solution? (Q=It) What mass of copper should have been deposited on the cathode (one Faraday = C)? What is the percentage yield of copper in the reaction?

20 Experiment 15 Title: THE REACTION OF METALS WITH ACIDS Aim To investigate the reaction of different metals with acids Apparatus Take note of the apparatus used. Chemicals Take note of the chemicals used Diagram Draw diagrams for the apparatus used. Method Write the method for the reaction of methods with dilute acids. To copper add a few drops of concentrated nitric acid Take note of any observations To copper add a few drops of concentrated sulfuric acid Take note of any observations Test the gas produced with potassium dichromate paper Fill a table like the one shown below for the reaction of each metal with dilute acid. How did copper react with concentrated nitric acid? How did copper react with concentrated sulfuric acid? Metal Appearance Reaction with Dilute Acid Magnesium Copper Ribbon. Dark but turns silvery on sanding. Turnings. Red-brown shiny solid Precautions Look up the hazard warnings for each chemical used. What precautions were taken to make the experiment safe? What precautions were taken to ensure fair results? Comment on each reaction with dilute acids taking place and include a balanced chemical equation for each. How does this data agree with the reactivity series? Select two metals and discuss, in terms of atomic theory, why one metal is more reactive than the other. Does copper react with dilute acids? Does copper react with concentrated sulfuric and nitric acids? What are the gases released in each reaction?

21 Experiment 16 Title: METAL DISPLACEMENT REACTIONS Aim To investigate the reaction of metals with solutions of other metal ions Apparatus Take note of the apparatus used. Chemicals Take note of the chemicals used Diagram Draw diagrams for the apparatus used. Method A small amount of each solution was To each solution, a... Observations... The above procedure was repeated Copy and complete the table shown to explain any observations. Where there is no observations write n/a or X. MgSO 4 CuSO 4 Al 2 (SO 4 ) 3 ZnSO 4 Mg / Cu / Al / Zn / Precautions Look up the hazard warnings for each chemical used. What precautions were taken to make the experiment safe? What precautions were taken to ensure fair results? Which metal replaced all the others? Why is this so? Explain the reactivity of this metal using the atomic theory. Select a reaction that took place. Explain the reaction, including balanced chemical equation. Divide this equation into two ionic half equations clearly indication oxidation and reduction. Which metal displaced none of the other metal ions? Why is this so? Classify the metals above in a reactivity series according to the results of this experiment. If sodium had to be added to solutions of the above metals, a metal displacement reaction would not occur. Explain this statement.

22 Experiment 17 Title: ACTION OF HEAT ON MATERIALS Aim To investigate the action of heat on a number of substances To identify any gases released by the decomposition of these substances Apparatus Take note of the apparatus used. Chemicals Take note of the chemicals used. Diagram Draw diagrams for the apparatus used. Method A small amount of the substance was put The substance was heated with Observations This was repeated for Carbon dioxide was tested by If it was present, Oxygen was tested using When present, it The presence of nitrogen dioxide was inferred by its colour. It is a You may choose to store your results in a table with three columns titled Substance, Observations and Gases Produced. Precautions Look up the hazard warnings for each chemical used. What precautions were taken to make the experiment safe? What precautions were taken to ensure fair results? Not all substances decompose on heating. Some examples were Although zinc oxide does not decompose on heating, it How does the stability of group 1 carbonates compare with that of group 1 hydrogen carbonates? Include a balanced chemical equation for the decomposition of a group 1 hydrogencarbonate. How does the stability of group 1 carbonates compare with that of other carbonates? Include a balanced chemical equation for the decomposition of a non-group 1 carbonate. Write balanced chemical equations for all the substances that decomposed in this experiment.

23 Experiment 18 Title: QUALITATIVE ANALYSIS 1 Aim To identify the cations and anions in a number of ionic compounds Apparatus Take note of the apparatus used. Chemicals Take note of the chemicals used. Diagram Draw diagrams for the apparatus used (e.g. for addition of alkali, flame test and heating thermally unstable compounds) Method, Observations and Inferences You can use the following format for conciseness: SUBSTANCE X Method Observation Inferences A white solid. Probably no transition metal cation A solution was made by adding distilled water Two drops of sodium hydroxide were added Excess sodium hydroxide was added A fresh solution was made and aqueous KI added A white precipitate formed The precipitate dissolved A yellow precipitate The compound is soluble Calcium, magnesium, aluminium or lead ions Lead or aluminium cations Lead (II) cations Dilute HCl was added to some solid X Substance X was heated in a boiling tube No reaction A brown gas formed No carbonates or sulfites The gas is nitrogen dioxide. X contains the nitrate anion Remember to identify both the anion and cation in each case!!

24 Experiment 18 Title: QUALITATIVE ANALYSIS 1 Precautions Look up the hazard warnings for each chemical used. What precautions were taken to make the experiment safe? The colour of the precipitate was not easily visible in coloured solutions, such as in the case of. What did you do to view the colour of such precipitates? Write a short paragraph about each compound. Each paragraph should show The test/s to find the identity of the cation. These should be supported by a chemical equation where possible. Not all tests results in a chemical equation (e.g. flame tests) - for these write no chemical equation since there is not one. Check your notes. Repeat the above for the anion. End each paragraph by stating the identity of the compound. For example: G was a white solid and readily soluble in water. G gave no visible change when sodium hydroxide was added and the mixture gently heated. G imparted a yellow-orange flame in a flame test. This showed the presence of sodium cations. G gave no effervescence when dilute acid was added, showing that neither sulfite nor carbonate ions were present. On adding acidified silver nitrate to a solution of G, a white precipitate formed confirming the presence of chloride anions according to the equation: Ag + (aq) + Cl - (aq) > AgCl (s)

25 Experiment 21 Title: TITRIMETRIC ANALYSIS Aim To carry out a titration to confirm the concentration of a previously prepared standard solution Apparatus Take note of the apparatus used. Chemicals Take note of the chemicals used. Diagram Draw diagrams for the apparatus used. Method Write your own method. You can use the notes or the video shown in class to help you ( Precautions Look up the hazard warnings for each chemical used. Titration Number Final Burette Reading First Burette Reading Titre Value What precautions were taken to make the experiment safe? What precautions were taken to ensure fair results? How were the burette and pipette washed? Write a chemical equation for the reaction taking place. Calculate the average titre value from your results. Clearly show and explain which titre values were used in this calculation and which were not used. Work out the concentration of the sodium carbonate solution. How does your result compare with the concentration calculated in the previous experiment? Which result do you think is better and why?

26 Experiment 22 Title: THE HALOGENS Aim To study displacement reactions in group 7 compounds. To observe precipitation of the different halides using silver and lead ions. Apparatus Take note of the apparatus used. Chemicals Take note of the chemicals used. Diagram Draw diagrams for the apparatus used. Method Write your own method to briefly explain how solutions of the three halide ions were prepared and the tests carried out on each one (using chlorine water, bromine water, iodine crystals, silver nitrate and lead (II) nitrate) Cl 2(aq) / Cl - Br - I - Br 2(aq) / I 2(s) / Ag + Pb 2+ Precautions Look up the hazard warnings for each chemical used. What precautions were taken to make the experiment safe? What precautions were taken to ensure fair results? Which halogen displaced all the other halide ions? Which halogen did not displace any halide ions? Explain the trend shown by the displacement reactions in terms of the reactivity of the halogens. Explain the difference in reactivity by referred to the atomic structure of the elemental halogens. Write a chemical equation for a displacement reaction of your choice. Divide the equation above into two ionic half equations. Write equations for the precipitation of a halide ion of your choice using silver and lead. Why was fluorine not used in this experiment? Why was astatine not used in this experiment?

27 Experiment 23 Title: PREPARATION OF PROPERTIES OF SULFUR DIOXIDE Aim To prepare sulfur dioxide using two different techniques. To test some properties of sulfur dioxide Apparatus Take note of the apparatus used. Chemicals Take note of the chemicals used. Diagram Method Write your own method. Observation and How did the sulfur burn? Was any smell observed? What happened to the universal indicator? What happened to the potassium dichromate paper? What happened to the potassium permanganate solution? Precautions Look up the hazard warnings for each chemical used. What precautions were taken to make the experiment safe? Write a chemical equation for the reactions taking place. What other method can be used to prepare sulfur dioxide? Include a balanced equation for this reaction. Of the two methods adopted, which is the best method to prepare pure sulfur dioxide? Why? How can the sulfur dioxide prepared in this experiment be collected? Why did the universal indicator change colour? Include an equation for the solubility of sulfur dioxide in water. In fact, sulfur dioxide is one of the pollutants responsible for acid rain. Why did the permanganate and the dichromate change colour? Give a few uses of sulfur dioxide.

28 Experiment 24 Title: PREPARATION AND PROPERTIES OF AMMONIA Aim To prepare and collect dry ammonia in the lab. To test some of the properties of ammonia. Apparatus Take note of the apparatus used. Chemicals Take note of the chemicals used. Diagram Draw diagrams for the apparatus used. Method Place some ammonium chloride in a boiling tube. Add some sodium hydroxide and heat the boiling tube. Test the gas by carefully smelling it, using damp red litmus and reacting with hydrogen chloride fumes. Take note of all observations. Place some ammonium chloride and calcium hydroxide in a flat bottomed flask. Set up the apparatus as shown in your diagram (notes chapter 11, p. 12, but collect ammonia in a gas syringe). Note the volume of gas collected and disconnect the syringe if the volume exceeds 90cm 3. Write a list of all the observations noted in this experiment Precautions Look up the hazard warnings for each chemical used. What precautions were taken to make the experiment safe? Write a chemical equation for the reactions taking place in both preparations. What effect does ammonia have on red litmus? Why? What happens when ammonia mixes with hydrogen chloride? Include a balanced chemical equation for this reaction. Why was the ammonia not dried using concentrated sulfuric acid? What other methods could have been used to collect ammonia? How is ammonia prepared in industry? What are some uses of ammonia?