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International Baccalaureate: Chemistry
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489% % uncertainty for Vapor Pressure = 0% % uncertainty for Partial Pressure = 0. 489% % uncertainty to absolute uncertainty = 0. 489*100.0/100 = ±0. 489 ∴ Absolute uncertainty of Partial Pressure = 100.000 kPa ±0. 489 Volume occupied by one mole of hydrogen at STP P1V1/T1 = P2V2/T2 100*0.037/292 = 100*V/273 V = 0.0346 dm3 % uncertainty for Pressure 1 = 0. 489% % uncertainty for Volume 1 = 0.0005/0.037*100 = 1.35% % uncertainty for Temperature 1 = 0.5/292*100 = 0.171% % uncertainty for Pressure 2 = 0% % uncertainty for Temperature 2 = 0% % uncertainty for
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They are all rather soluble in dilute acids. The compound to be prepared is potassium tris(oxalato)ferrate(III) trihydrate. It is an octahedral transition metal complex in which three bidentate oxalate ions are bound to an iron centre. The general equation of the reaction is; (NH4)2[Fe(H2O)2(SO4)2]*4H2O + H2C2O4*2H2O FeC2O4 + H2SO4 + (NH4)2SO4 +8H2O H2C2O4*H2O + 2FeC2O4 + 3K2C2O4*H2O + H2O2 2K3[Fe (C2O4)3*3H2O + H2O A titration with potassium permanganate (KMnO4) will then be used to determine the amount of metal in the oxalate complex.
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Magnesium Oxide, depends on how much Magnesium is added. The dependent variable will be the mass of Magnesium Oxide, this is a measured variable as the mass of oxygen can be calculated and will enable us to determine the formula for Magnesium Oxide. Controlled variables: 1. Container used 2. Surface area of Magnesium 3. Concentration of oxygen in the container 4. Temperature of flame Controlling variables: 1. A crucible with a lid is used and is filled with a layer of filter paper, in order to allow combustion in a closed environment, preventing the loss of Magnesium oxide powder. 2. Magnesium ?ribbon? will be used in all cases. 3.
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We can conclude that the experiment gave a reasonably accurate value for the number of moles of water of crystallization in oxalic acid
This experiment was repeated three times with the same variables and measurements to get an average of the readings collected for more accurate results. Quantitative Data: RAW DATA Experiment Mass of weighing bottle (+/- 0.01g) Mass of weighing bottle and oxalic acid crystals (+/-0.01g) Mass of oxalic acid crystals (+/- 0.02g) Volume of oxalic acid solution (+/- 0.3cm³) Start volume of burette (+/- 0.5cm³) End volume of burette (+/- 0.5cm³) 1 13.4 14.9 1.5 25.0 0.0 24.6 2 13.4 14.9 1.5 25.0 0.0 24.8 3 13.4 14.9 1.5 25.0 0.0 24.7 PROCESSED DATA Experiment Volume of oxalic acid solution (+/- 0.3cm³)
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The larger the alcohol molecule, the more bonds will be broken and formed, and therefore more heat will be produced. Using experiments, the standard enthalpy of combustion of an alcohol can be found, buy first finding the heat released during the reaction using the equation Heat=mass of water ×specific heat capacity of water ×rise in temperature of water Note: The specific heat capacity of water is 4.18 Jg-1°C-1. and then finding the number of moles of alcohol burnt, and dividing the heat by this number.
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The second equation for this process is the following: Hydrochloric acid being titrated by sodium hydroxide. HCl + NaOH → NaCl + H2O Calculations: Moles of HCl= n=0.02dm3 x 1.00moldm3=0.02 moles of HCl Moles of NaOH n=0.0107dm3 x 0.10moldm3= … as 1:1 relation with HCl then n=0.00107 moles of HCl Total number of moles used=0.02-(0.00107*10)=0.00930 moles As 2:1 relation with CaCO3 then 0.00932=0.00465 moles of CaCO3 Conversion to grams= 0.00465 moles x 100.08 grams1.00 moles=0.46537 grams of CaCO3 Percentage by mass= 0.465g0.60 g x 100=77.50% Analysis: From the graph obtained, the point of equivalence can´t be easily identify by just
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Trial 1 113.3g Temperature Change of CuSO4 Solution (°C)(±0.5°C) Trial 1 0°C Temperature Change of Cu + Zn2+ solution (°C) (±0.5°C) Trial 1 38°C Mass of CuSO4 Solution (g) (±0.05g) Trial 2 25.0 grams Mass of Zinc Powder (g) (±0.05g) Trial 2 4.0 grams Mass of Copper Calorimeter (g) (±0.05g) Trial 2 113.3g Temperature Change of CuSO4 Solution (°C)(±0.5°C) Trial 2 0°C Temperature Change of Cu + Zn2+ solution (°C) (±0.5°C) Trial 2 38°C Average of Temperature rise (ΔT): 38°C+38°C 2 trials= 38°C This value will be used to calculate the enthalpy change throughout this experiment.
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It is the part of chemistry that studies amounts of substances that are involved in reactions. Stoichiometry is the branch of chemistry and chemical engineering that deals with the quantities of substances that enter into, and are produced by, chemical reactions. The word stoichiometry derives from two Greek words: stoicheion (meaning "element") and metron (meaning "measure"). Stoichiometry deals with calculations about the masses (sometimes volumes) of reactants and products involved in a chemical reaction. WHY, WHAT AND HOW All reactions are dependent on how much stuff you have.
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Independent Volume of the gas collected (H2, CO2) The amount of gas collected for each experiment will depend on the Controlled 1. Mass of Calcium Carbonate (both marble chips and powdered form) 2. Mass of Magnesium (both ribbon and powder) 3. Volume of Hydrochloric Acid 4. Apparatus Used 1. The masses of the substances utilized will remain constantly fixed during the experiment 2. 50 cm3 of HCl will be used for every trial ? 550 cm3 in total 3. The apparatus used will remain the same throughout the whole experiment Chemical Reactions: Mg + 2HCl ? MgCl2 + H2 1.
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Bomb calorimetry. The goal of this experiment was to use temperature data over time from combustion reactions to calculate the heat released and then produce an experimental value for the heat of formation of naphthalene.
A substance with a known heat of combustion such as benzoic acid may be used to determine the heat capacity of the calorimeter. Once that value is known, the heats of combustion for other chemical samples are also found by combusting them. The determined heats of combustion may be used to find experimental values of the standard heats of formation of the different chemicals combusted. The chemical equations for the combustion of the organic sample and the standard heats of formation of the combustion products (carbon dioxide gas and liquid water)
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(IEA, 2008) Significantly, 77% of electricity in Australia (IEA, 2008) is produce from the combustion of coal. ?The Sydney Morning Herald? reported that an average Australian person uses 5 tons of coal each year for electricity (Manning, 2012). Coal is relatively inexpensive in Australia as there are high content of coal viable, and this is one of the main reason for the continuous use of coal to generate electricity (Australian Coal Association , 2011). ?Mongbay?, an environmental science website, showed that it costs up to a maximum of 180 dollars to purchase a metric ton of coals in Australia (Butler, 2012).
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Hypothesis: It is hypothesised that if the current increases then mass deposited on the cathode will increase at a proportional rate. Variables Independent ? Magnitude of Current flowing into the electrolytic cells. Dependent ? Mass of Copper deposited at the cathode after electrolysis (g) Controlled Variables: These variables affect the experiment results and should be controlled by being kept constant throughout the experiment to gain a reliable result. - Concentration of Copper (II) Sulphate solution. The higher the concentration of Copper (II)
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Objective: To investigate the order of oxidizing ability of the halogens Cl2, Br2, and I2 in aqueous solution
About 1mL of Potassium bromide solution is added to each of two test tubes 2. About the same volume of chlorine water is added to one of these tubes and the other was added with the same volume of iodine solution 3. The test tubes is shake and the color changes is noted-(if any) 4. A few drops of hexane are added to each tube, shake and allow it to settle and the color of each layer is noted. 5. Reaction that taken place is observed and a copy of result are completed in table 11.1.
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The volumetric flask was cleaned and rinsed with distilled water 2. 5 ml of NaOH solution was transferred into the volumetric flask using funnel and the remaining NaOH was washed into the flask several times using distilled water. 3. The NaOH solution was topped up to 250 cm3 with distilled water , the cap was closed up and the flask was rotated several times to get a homogenous solution. 4. The solution was poured into a clean and dry beaker , the beaker was labeled and was covered with a watch glass and put it aside.
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