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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)
The lower melting temperature oils tend to replace fats in marine animals e.g. whales, because fats would be too viscous or solid at sea temperatures. Fats contain mainly saturated acids such as: * Hexadecanoic acid: C15H3CO2H, which is commonly known as palmitic acid. CH3 (CH2)14 COH * And octadecanoic acid: C17H35CO2H, which is commonly known as stearic acid. CH3 (CH2)16CO2H While oil contains a high proportion of unsaturated acids such as oleic acid, C17H33CO2H. Cis - CH3 (CH2)7CH=CH (CH2)7CO2H Oleic acid is mono - unsaturated acid since it only has one carbon - carbon double bond.
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To overcome this problem I will need to let the gas cool before measuring the volume, and may need to cool the gas as it enters the gas syringe. At room temperature and pressure, the volume of one mole of gas is 24dm�. From this I can find the number of moles of gas each equation will produce, and therefore how much copper carbonate to use. I will use the formula: Volume(dm�) = Number of Moles x 24dm� 80cm� = 0.08dm� Number of moles = 0.08 24 = 0.00333 moles To get a idea of which equation will give off
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To work out H1 we need to find the energy transfer per 1 mole of calcium carbonate, but first I need to calculate the number of moles in calcium carbonate: Number of moles = Mass Mr = 2.39 100.1 = 0.02387612388 moles = 0.024 moles (3 d.p.) Therefore, H1 = - 0.84 0.024 = -35 J mol-1 Experiment 2: Calculating the H2 for the reaction between CaO and HCl. Using the formula: Density = Mass Volume , We can work out the mass of liquid (HCl)
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Remove the air space below the tap and use the wastage beaker to catch any of the acid. Remove the funnel 2. Use the pipette to take 25cm3 of the sodium carbonate solution and place it in the conical flask. Add 1-2 drops of methyl orange indicator. Place the conical flask directly under the burette. 3. Take note of the initial reading of the acid in the burette and titrate until the indicator changes from a yellow colour to a pink colour. Take note of the final reading of the acid in the burette. 4. Repeat a minimum of three times, and for each, calculate the volume of acid used by subtracting the initial reading from the final reading.
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In order to do this you will need to select a suitable concentration for the HCl acid to be diluted to. As we already know according to the balanced equation 1 mole of Ca(OH)2 reacts with exactly 2 moles of HCl, so you should try and make HCl two times concentrated as the Ca(OH)2. So in order to make HCl twice as concentrated as Ca(OH)2 you will do the following calculation: 0.0135 x 2 = 0.027 mol dm-3 . This means the 2 mol dm-3 will need to be diluted to 0.027 mol dm-3 however this is to difficult to measure so a better concentration to dilute HCl to would be 0.02 mol dm-3.
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Method 1. To start off, I am going to make my standard solution. I will do this by weighing 2.65 grams of sodium carbonate in a glass bottle on a mass balance. But first, I will weigh the bottle, measure the mass of the bottle and then change the scale to read 0 grams. I will then add 2.65 grams of sodium carbonate into the bottle. 2. I will then wash a 250ml volumetric flask using distilled water. The reason being is so that it removes any other molecules from previous experiments.
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which could alter the results of the titration and a sensible volume for the hydrochloric acid is 100cm3 so the titration can be repeated. Preparation of Hydroxide Solution 1. While carrying out this method it is advisable to wear goggles, gloves and a lab coat to avoid any unnecessary accidents usually associated with alkalis due to their corrosive properties. 2. The mass of the hydroxide being used firstly needs to be calculated by using an average molecular mass of the metals added to the hydroxide group which is 122 and gives the mass needed by 122�1000x 100x 0.01=0.122g then it is weighed out in a paper boat using an accurate balance, which has been zeroed.
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Finally postmodernists belief that religious organisations are decreasing with increase of fundamentalism. This statment is implying that Religion helps people in defferent ways, to cope and adapt to changes of new societies and enables a structure for their lives. Religious Organisations differ in many ways, they scale in terms of rigid hierarchy, ie.e from Roman Catholic Church with pope to just local priests. Sociologists have classified religious oragnisations into types. These main types are Churches, Demoninations, Sects and Cults. However these are just ideal types as it is challaging as some groups fall in between these types, therefore difficult to catergorize.
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Weigh the weighing bottle. * Before we begin the experiment we will make sure that the desk, all the instruments and apparatus are clean. We will follow the method carefully in order to get precise and reliable results. * We will also record all the results in the table provided, in order to analyse and calculate, when the experiment will be completed. Skill A - Analysing Evidence and Drawing Conclusions Results: Mass of CaCO + Weighing Bottle 15.01 g Mass of CaO + Weighing Bottle 15.01g Mass of Empty Weighing Bottle 12.59 g Mass of Empty Weighing Bottle 12.59
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Warm the acid in the pear shaped flask until it is almost boiling and turn off the electrothermal mantle. 3. Carefully remove the stopper and put the dropping funnel in position, as shown in the diagram. 4. Add the mixture containing the ethanol at such a rate as to maintain the boiling of the mixture in the pear shaped flask. Collect the distillate and write down all observations in the space below. 5. Carry out the following tests on the distillate and record your observations.
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The rate equation cannot be calculated from the balanced chemical equation, but has to be found through experimental procedures. The overall rate equation takes the form of: Rate (mol dm-� s-1) = K [A]a[B]b[C]c Where: [A], [B], and [C] represent the concentration of the reactant in mol dm-�. The indices 'a', 'b', and 'c' show the order of the reaction with respect to each of the reactants A,B, and C. the sum of all the indices is called the overall order of the reaction. 'K' is a constant of proportionality known as the rate constant, and its units depend on the order of reaction.
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They all produce different types of exhaust emissions because of the ratio of air to fuel that they use. Conventional engines use high levels of fuel and so produce more nitrogen oxides. Lean-burn engines use high amounts of air and so produce more hydrocarbons. Diesel engines are like lean-burn engines, but produce high levels of particles and smoke.vi Acid rain NOX emissions are oxidised in the atmosphere to form NO2. This then reacts with OH radicals to form HNO3, or nitric acid. This then falls to Earth as acid rain. This can be shown as the reactions below. 2NO + O2 2NO2 NO + O3 NO2 + O2 NO2 + OH HNO3 vii Heterogeneous Catalyst A heterogeneous catalyst means that the reactant is in a different physical state to the catalyst.
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1 2 3 4 23.3 cm� 22.7 cm� 21.2 cm� 22.9 cm� Mean titre is: (22.7 + 22.9) / 2 = 22.8 On average, 25.0 cm of LiOH required 22.8cm of 0.100 mol of HCl Number of moles of HCl used: 22.8 / 1000 x 0.1 = 0.00228 mol Number of moles of LiOH: 1:1 ratio so, 0.0228 Number of moles of LiOH present in 100cm of solution: 25cm = 0.00228 x 4 = 0.00912 RAM of Li is therefore : 1/ 0.00912 x 0.08 = 8.77 Hazard concepts: Lithium reacts violently with water to give off flammable hydrogen gas and corrosive dust.
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as well as the white magnesium oxide. The oxide is also produced on heating in steam. Hydroxides are only ever produced using liquid water. For aluminium, aluminium powder heated in steam produces hydrogen and aluminium oxide. The reaction is relatively slow because of the existing strong aluminium oxide layer on the metal, and the build-up of even more oxide during the reaction. For silicon, there is a fair amount of disagreement in the books and on the web about what silicon does with water or steam. The truth seems to depend on the precise form of silicon you are using.
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If plants become deficient in these elements fertilisers can be used to replace them. If a plant does become deficient in one of these elements it may be best to use an inorganic fertiliser, as there is a fast increase of mineral ions and are therefore immediately available to plants, whereas organic fertiliser must be converted by micro-organisms in the soil before it can be used. This can also be seen as an advantage though as the slow release of mineral ions means that there is a steady supply to plants.
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This can also save farmers money to purchase chemical fertilizers elsewhere. Unlike inorganic fertilizers, organic fertilizers do not damage soil structure; they can help to reduce soil erosion by improving the soil structure such as the water-holding properties. Improving the water-holding capacity of the soil also gives a distinct advantage to areas that have arid climates. As a result of improving the soil structure of lands, it decreases the probability of desertification. Using organic materials also gives advantages to areas that have relatively cold climate, as organic fertilizer can generate heat and are therefore able to warm up cold lands, increase the growth rate of crops.
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There is a less chance of blocked arteries causing the amount of blood flowing to decrease and thus causing cardiac arrest. (Ling, 1994) Aspirin has been becoming increasingly popular with patients that have experienced a heart attack to avoid any recurrence taking place or tissue death surrounding the cardiac muscle. Aspirin can also be defined as a non-steroidal anti-inflammatory drug and Aspirin being one of the first to be classed as one. (Greenlaw, 2005) These are medications with analgesics that reduce fever and have anti-inflammatory effects.
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The results that I get I would then record them in my results table. Risk Assessment: Name of hazard Hazard Safety Precautions Emergency action Risk level (Low/Medium/High) Image Pipette Pipettes are used for transferring chemicals from one place to another, they can also be used to measure the amount of chemical being transferred, whilst using the pipette it could have some leftover of chemical/acid which could cause irritation. You should first make sure that the entire chemical has been emptied out from the pipette and then you should make sure that you handle it with care.
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Mat Risk assessment Name of hazard Hazard Safety Precautions Emergency Action Risk Level Bunsen Burner (Could start a fire) You may not see the flame and accidentally burn yourself or someone else could burn themselves too. Make sure you don?t place your hands anywhere near the flame, tie the hair up so it isn?t in the way. Always make sure that you use a safety mat as this prevents fires. When you have finished using the Bunsen burner you should turn it off to prevent someone from burning themselves. If you have a burn on your hand, place under cold water then seek medical attention, if anything worse occurs such as clothes catch fire which spreads then seek immediate medical attention.
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The chemical that was being used in the first flame test could stick on the wire and when it is used with another chemical it will give the wrong inference. Other factors that could affect the contamination might be dirt particles on the surface that could stick on the wire if it is left on an unclean surface. Misreading Inferences: There are many misreading?s of inferences that could be done overall. The appearance of the chemical could change in colour over time; this will directly lead onto misreading the inference.
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Potassium is a group 1 element; therefore, its colour is white. This is because group 1 elements do not possess a d orbital that the electrons can move between by absorbing light and allowing various colours to be observed. Transition metals have at least one stable ion that contain d orbitals which are incompletely filled with electrons. Their colours vary on the metal ion charge and the number of ligands (groups of atoms) which are attached to them. For example, Nickel appears to be green with a charge of +2. Iron appears to be brown with a charge of +3.
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1. Then released the acid into the conical flask. Pipette 3 drops of phenolphthalein in to flask, swirl it to make sure it has mixed completely. 1. Using a burette clamp, secure it onto a retort stand. Rinse the burette with the alkali (NaOH) and, with a beaker underneath, let the sodium hydroxide run through the bottom of the burette by leaving the tap on, make sure there are not any bubbles present - this is to avoid any inaccurate reading later on. 1. Fill the burette with NaOH up to where the bottom of the meniscus hits 0, again reading from eye level to avoid errors in measurements.
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0.0 25.0 360.0 28.0 30.0 28.5 420.0 28.0 60.0 28.0 480.0 28.0 90.0 28.0 540.0 28.0 120. 28.0 600.0 28.0 150.0 28.0 660.0 28.0 180.0 28.0 720.0 28.0 210.0 28.0 780.0 28.0 240.0 28.0 840.0 28.0 270.0 28.0 900.0 28.0 300.0 28.0 From the graph of Temperature of mixture against Time, ΔT2 = 3.5°C Part III: 25ml of 1.75M Ammonia solution + 100ml of 0.5M HCl Initial temperature of Ammonia solution = 25.0 Initial temperature of HCl = 24.0 Table 3: Time(seconds) Temperature of mixture() Time(seconds) Temperature of mixture() 0.0 24.5 360.0 29.0 30.0 28.0 420.0 29.0 60.0 28.0 480.0 29.0 90.0 29.0 540.0 29.0 120.
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Sodium peroxide has a pH of 14 when dissolve in water. The reaction is an exothermic reaction which generates a large amount of heat which is sufficient to burn shredded paper. Magnesium oxide on the other hand is far less reactive if compared to sodium peroxide. When magnesium oxide is added to water, the reaction is not noticeable. Magnesium hydroxide is yielded as shown below: Magnesium hydroxide has low solubility in water which in turns giving out less hydroxide ion which indicates magnesium oxide has a significant low basicity compared to sodium peroxide.
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The formula reacts with the OH of sodium hydroxide in exactly the same way as HCl. HKC8O4H4 + NaOH NaKC8O4H4 + H2O (iii) Acid-Base Titration and End Point Reactions between acids and bases that are dissolved in water occur almost instantaneously: they occur as fast as the two solutions can be mixed. These reactions also tend to go to completion: react until the entire limiting reagent is consumed. When exact stoichiometric amounts of acid and base have been mixed, the reaction is said to have reached the equivalence point.
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