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AS and A Level: Inorganic Chemistry
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Top tips for writing reactions
- 1 Remember to balance the charges on any ionic compounds. The common ions are NO3-, SO42-, OH- and CO32-.
- 2 Do not forget to put state symbols on all of your balanced reactions.
- 3 Each side of the reaction must have the same number of atoms on it. Think about a balanced seesaw.
- 4 Your three main acids that you will use have the formulae HNO3 (nitric acid), H2SO4 (sulphuric acid) and HCl (hydrochloric acid).
- 5 Remember that all metal hydroxides and metal oxides are bases. This will help you when using word equations to figure out your products.
Five common mistakes students make when studying inorganic chemistry
- 1 When observing a gas being produced, you would not write “I saw a gas” as most gases are invisible. Instead you should write “I saw bubbling / fizzing / effervescence”.
- 2 When asked to write a word equation, students often write a symbol equation and vice versa. This will get you no marks in the exam.
- 3 - When asked for “standard conditions” people often say “room temperature”. This is not sufficient. You must say 25 degrees celsius (298K). Other standard conditions you must know are 1 atmosphere of pressure and concentrations of 1 mol dm-.
- 4 If you are asked to state a colour change you must state the initial and final colour.
- 5 Students often give group 2 metals a 1+ charge. Remember that all group two metals (Be, Mg, Ca, St, Ba, Ra) have a 2+ charge.
Five word equations that you must know
- 1 Acid + base / alkali = salt + water (eg HCl + NaOH becomes NaCl + H2O)
- 2 Metal carbonate = metal oxide + carbon dioxide (eg CaCO3 becomes CaO + CO2)
- 3 Metal + oxygen = metal oxide (2Mg + O2 becomes 2MgO)
- 4 Metal + water = metal hydroxide + hydrogen (eg 2Na + 2H2O becomes 2NaOH + H2)
- 5 Metal oxide + water = metal hydroxide (eg CaO + H2O becomes Ca(OH)2)
+ 6H2O Percentage Yield Calculation (NH4)2Fe(SO4)2.6H2O --> 2K3(Fe(C2O4)3) + 6H2O Molar ratio 1 : 1 Actual Yield 4.86g mol= 0.0128 mol -1 mol= 0.0128 mol -1 mass= 5.03g mass=6.28g GFM= 392g GFM= 491.1 Mol= mass/GFM Mass= GFM x mol Mol=5.03/392 Mass= 491.1 x 0.0128 Mol= 0.0128 Mass= 6.28g Theoretical Yield = 6.28g Percentage Yield =Actual Yield x 100 Theoretical Yield = 4.86g x 100 6.28g = 77.39% Discussion a) Reasons for the fact the yield of Potassium Trioxalatoferrate are less than 100% are: * Products may be lost during the decanting stage * Products may be washed away * Products may be left on filter paper * Products may react with chemicals in the beakers from previous experiments b)
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of empty boat after = 26.88g - 1.926g = 24.954g Now that I have the mass of the crystals used I will be able to calculate the number of moles of CuSO4 that I have by using the equation: Number of moles = Mass Molar Mass n = m Mr n = 24.954 249.6 n = 0.099975961 mol Now I know how many moles of CuSO4 I have I can work out the concentration of the solution (CuSO4.5H2O)
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The volumetric flask was shaken upside down for several times. 5. 25.0 cm3 of sodium carbonate solution was pipetted into a conical flask. 6. 3 drops of methyl orange indicator was added into the conical flask. 7. Hydrochloric acid was poured into a burette. 8. The initial burette reading was recorded. 9. The reaction mixture in the conical flask was titrated with hydrochloric acid until it just changes from yellow to orange. 10. The final burette reading was recorded.
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Therefore, of the three halogenoalkanes, that containing Chlorine should be the most reactive. Bond Bond Enthalpy kJ mol-1 C-Cl 340 C-Br 280 C-I 240 There is, however, a contradicting theory. When looking at bond strength, C-I needs to be applied with the lowest amount of energy in comparison to the other two for it to be broken. Understandably, this greatly contradicts the previously given theory according to bond polarity. Within any reaction that occurs, the reactants must collide with sufficient energy to react, which is known as activation energy. There are more likely to be more molecules with the required activation energy to break the C-I bond than the C-Cl at a given state, meaning that a halogenoalkane containing Iodine is the most reactive.
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Chem Lab report. Objective: To determine the concentration of potassium manganate(VII) solution using ethanedioic acid as a primary standard in volumetric analysis (redox titration)
solution. Potassium manganate(VII) solution does not oxidize ethanedioic acid at low temperatures. As a result, the solution should be heated to 60? in order to lead a reaction to occur. The above 2 half equations were combined to one equation: 2MnO4- (aq) + 6H+ (aq) + 5(COOH)2 (aq) 8H2O (l) + 2Mn2+ (aq) + 10CO2 (g) From the above equation, The volume of potassium manganate(VII) solution used in the titration was measured by taking the difference of burette reading before the reaction and that when the color of reaction mixture turns from colorless to a permanent light purple. It was then used in calculating the concentration of potassium manganate(VII) solution. ? no.
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= c � v = 0.1 � 0.02945 n = 0.002945 mol n(CH3COOH) = 0.002945 mol (n(NaOH) and n(CH3COOH) are a 1:1 ratio) m = n mr mass(CH3COOH) = 0.002945 � 60 = 0.1767 grams The mass of ethanoic acid in the sample of Aceto vinegar is: 0.15906g n(NaOH) = c � v = 0.1 � 0.02651 n = 0.002651 mol n(CH3COOH) = 0.002651 mol m = n mr mass(CH3COOH) = 0.002651 � 60 = 0.15906 grams The mass of ethanoic acid in the sample of Cornwalls vinegar is: 0.15906g n(NaOH)
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1) From the graph of the solubility curve, it can be determined that: a) the solubility of potassium nitrate at 50�C is approximately 74g/ 100g of H2O. b) the temperature at which the solubility of potassium nitrate is 80g/100g of H2O, is approximately 53.5�C. c) the maximum amount of potassium nitrate that would dissolve in 100g of water at 60�C is 90g. d) the temperature at which 20g of potassium in 25g of water (80g/100g of H2O) needs to be heated in order to completely dissolve must be greater than 53.5�C. (53.5�C is the temperature at which first signs of crystallisation occur.
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Unless this test is carried out immediately after the flexural strength test on the beam, the broken portions should be returned to the curing tank until required. c. Place the broken portion of the beam in the test jig as per the sketch. d. Place the jig centrally in the compression test machine (no packing is to be used between the specimen and the auxiliary platens or between the compression machine platens and the auxiliary platens).
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The dimensions of the three cubes were measured with calipers. No "under size" or "oversize" cubes were recorded. 5. The cubes were weighted 6. Test machine platen was wiped with a dry cloth. 7. The cube was placed centrally on the lower platen of the test machine with the rough as-cast top surface of the test cube vertical not in contact with the platens. 8. The appropriate loading rate was selected for the cube tested. Pacerate for 150mm cubes is 338kN / min.
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Set the meter to read 7.0 . 4. Place the beaker under the burette containing NaOH and, making sure the alkali does not fall directly on to the electrode, add 1 drop of 0.1M NaOH. Stir gently to ensure thorough mixing & record the pH in Table 1. 5. Add more NaOH to make the total volume added 1.0 cm3. Measure & record the pH in Table 1. 6. Add more NaOH to make the total volume added 5.0 cm3.
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By using the mass change one can determine the percent of the hydrate. Hypothesis: For this lab I made two hypothesis'. The first one states that in the CuSO4* 5H2O; a majority of the compound is cupric sulfate rather than the hydrate. The second one states that the NaCl is already a anhydrous compound based on the fact there wasn't really any significant mass change after heating. Materials and Equipment: 1 hot plate 1 evaporating dish 1 glass stirring rod 1 crucible tongs cupric sulfate pentahydrate (CuSO4* 5H2O)
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In addition Pip sees Joe as his equal "I always treated him as a larger species of child and as no more than my equal". Pip feels as if Joe is the only one who cares for him and he feels like he can trust Joe. He also looks up to Joe as he is the only manly figure that Pip aspires to be. Although Joe is the only one that seems to care for Pip, he does not play an important role in society or in the Gargery household as Mrs.
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The predicted mass of CuO is 0.72g. The second hypothesis is the theoretical yield of copper from the second reaction. As demonstrated below - Materials and Equipment: (From Handout) 1.00g Cu2(OH)2CO3 copper(II) carbonate basic 0.50g C carbon black ring stand with ring clamp and clay triangle crucible and lid crucible tongs 2 weigh boats glass stir rod metal spatula gas burner and hose igniter 50 ml beaker hot plate Procedure (from handout) Part 1 1. Mount an iron ring on a ring stand, equip with a clay triangle and obtain a Bunsen burner, crucible and cover.
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Results & Calculations Time (s) / Temperature ( ) Reaction 1 Reaction 2 Reaction 3 Reaction 4 Reaction 5 Reaction 6 0 24.8 24.0 24.5 23.8 24.2 24.0 5 31.0 31.5 30.0 32.0 44.0 35.0 10 34.5 34.5 33.0 35.0 50.0 36.5 15 35.5 35.5 33.5 36.0 53.0 37.0 20 36.0 35.8 34.0 36.2 53.5 37.0 25 36.2 35.8 34.0 36.5 53.5 37.0 30 36.2 36.0 34.0 36.5 53.5 37.0 35 36.2 36.0 34.0 36.5 53.2 37.0 40 36.2 36.0 34.0 36.2 53.0 37.0 45 36.2 36.0 34.0 36.2 53.0 37.0 50 36.2 35.8 34.0 36.2 53.0 36.8 55 36.0 35.8 34.0 36.0 52.8 36.8 60 36.0 35.8 34.0
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� 0.2 (�C) � 0.2 (�C) 1 100 � 0.5mL of 2.93 21 22 H2O 2 100 � 0.5mL of 2.87 20.9 26.5 0.50M HCl 50.0 � 0.5mL 3 of 1.0M HCl ; N/A 20.4 26.7 50.0 � 0.5mL of 1.0M NaOH Observation Notes: *Since these data is collected by us (Laura and Rhona), we have some observation notes about reaction 1, 2 and 3. Reaction 1: Temperature change is really slow. Reaction 2: Temperature raises a lot, but not very fast. Reaction 3: Temperature increases very fast.
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The alumina is dissolved in molten cryolite (Na3AlF6). Then mixture is then heated to approximately 980oC, (aluminium oxide usually melts at a higher temperature, but due to the added aluminium fluoride, a considerable amount of energy is saved). The mixture is then placed in a carbon lined bath and a large electrical current is passed through it. This forms aluminium at the cathode and oxygen gas at the carbon anode. The oxygen gas reacts with the anode to give off carbon dioxide gas.
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--> Cl2(g) + H2O(l) Cl2(g) + 2I- (aq) +2H+ (aq)--> I2(aq) +H2O(l) + 2Cl- (aq) I2(aq) + 2S2O32-(aq) --> 2I-(aq) +S4O62-(aq) Requirements Volumetric flask(250cm3). Burette(50cm3). Pipette(25cm3). Pipette filler. Page1 Conical flask (250cm3). Dropper. Wash bottle. White tile. Burette stand. Balance. Weighing bottle. Beakers. Measuring cylinders. (50cm3, 100cm3) Commercial bleaching solution. Potassium iodide crystals. Ethanoic acid ( about 1M ) Standard sodium thiosulphate solution Starch solution (Freshly prepared). Procedure 1. Volumetric flask, conical flask, burette, pipette, weighing bottle, beakers were washed with tap water. 2. Step (1) was repeated but with deionized water at this time. 3. The tissues were used to dry the apparatus.
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Titrations are important to understand how acids and bases react with each other, ways to understand detection of experimental error, and to experimentally calculate or figure out what a chemical or substance consists of or the properties it can contain. Titrations are a key tool in industry laboratories and for educational purposes. The right technique and precision of an experiment, accurate results can be achieved. Accuracy and precision can improve in a titration when effort as well as repetition is applied.
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Therefore the best volume of solution to use per titration will be 25cm3, as it allows the acid to have a concentration greater than or less than the assumed 0.1 mol dm-3. To produce reliable results, I will need to complete three titrations with a range of no more than 0.1cm3. Taking into account a rough titration and any anomalous results, I will probably need to do at least six titrations, which will require 150cm3 of sodium carbonate solution. The solution will be made up in a volumetric flask, which has set volumes.
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Then a solution of 5.08g oxalic acid dihydrate in 30cm3 of water was added. The mixture was heated cautiously, with continuous stirring to boil. Then the yellow precipitate of hydrated iron(II) oxalate was allow to settle. The supernatant liquid was poured off and the precipitate was washed once with hot water by decantation. A hot solution of 7.49g of potassium oxalate monohydrate in 20cm3 of water was added and the mixture was cooled to 40?. 20cm3 of 6% hydrogen peroxide solution was added a few drops at a time with continuous stirring. The temperature must be kept below 50?.
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The hydrogen atom is left with a slight positive charge as electrons exist further away from it due to the presence of chlorine in the molecule. Instantaneous Dipoles Many small molecules do not possess permanent dipoles because the atoms that are bonded together all have the same, or very similar, electronegativity. This means that on average, the shared electron cloud is evenly distributed across the atoms. However, a temporary or instantaneous dipole can arise because the electrons are in constant motion and at any particular moment, they may not be evenly distributed over the atoms in the molecule.
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* Ensure that the acid mixture is properly mixed by shaking. Then fill a graduated pipette with 25cm3 of the acid mixture and pipette this into a 250cm3 conical flask. * You will not need to add any indicator as KMnO4 is self indicating; the end point has been reached when a permanent pale pink colour appears. * This reaction will only take place above 60 degrees Celsius, therefore heat the conical flask before titrating to a little over 60 degrees, using a Bunsen burner.
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It is mostly used in medicine like pain killers and also they are used for reducing fever. Aspirin is made by reacting salicylic acid with acetic anhydride. The human generation already knew how useful salicylic acid for pain. It was until the 19th century when we learned how to make mass production of aspirin and how to cope with the toxic side effects. Aspirin has many pharmaceutical uses; the most important is the cure for any kind of pain. It can also treat arthritis because it has an anti-inflammatory effect and also reduce fever. One of the majors side effects gastritis this gives stomach aches.
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You should wear all the safety equipment at all times during the experiment. Eye Protection: Make sure that your eyes are fully protected. Goggles should be worn at all times during the experiment in the laboratory. Laboratory Coats: Lab coats should be worn during experiment to avoid damage to your clothes and skin. Laboratory environment: Experiment should be taken place in a wide space and try to avoid having any unwanted stuff around you as it can come in contact with the chemicals and cause damage.
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The molar enthalpy for Magnesium should only vary because of human error. All three calculated enthalpies should be very close, because the molar enthalpy of Magnesium is dependant upon only Magnesium's properties, not the other reactants'. Materials * 1 mol/L Aqueous Ethanoic acid * 1 mol/L Aqueous Hydrochloric acid * 1 mol/L Aqueous Sulfuric acid * Magnesium shavings * 3 calorimeters * 3 stop watches * Three 50mL graduated cylinders * Three 100mL beakers * Digital scale * Safety glasses Procedure 1. Apply safety glasses, and gather all apparatus. 2. Using the digital scale, measure out three samples of approximately 1/4 g of magnesium.
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