Chemistry unit C3 OCR Board

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Flashcards on Chemistry unit C3 OCR Board, created by absaroke on 03/08/2016.

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a) what does rate of reaction measure? b) what part of a reaction is the fastest at generating product? c) which part is the slowest?why? a) the quantity of product made within a set period of time b) the beginning c) the end as the majority of reactants are used up and become more spread out- meaning there are fewer successful collisions in a set period of time
a) what are the units for measuring the rate of reaction? b) when is the shorter unit of time used? a) g/s (grams per second) or cm3/s (centimetre cubed per second) and g/min (grams per minute) or cm3/min (centimetre cubed per min) b) when there is a fast reaction which takes place in much less time
a) how can rate of reaction be calculated? b) graphically? a) amount of product made divided by the time taken to make it (answer with appropriate units if divide grams by minutes, g/min) b) choose part of the graph where their is a straight line of best fit section and draw a gradient triangle, using the axis instead of squares for the calculation
a) what is a limiting reactant? b) what does directly proportional mean in terms of limiting reactant? a) a reactant which isn't in excess and gets used up in the reaction. b) it means that the amount of product formed is the same as the amount of limiting reactant used in the reaction.
a) interpolation a)
a) why are successful collisions limited in a reaction where the number of reacting particles are limited? a) because the reacting particles can only collide successfully a certain amount of times until the product is formed which is directly proportionate to the amount of reactans
a) which four things increase the rate of reaction? a) 1. Temperature 2. Concentration 3. Surface area 4. presence of a catylist
a) how does temperature increase rate of reaction? a) As the temperature increases, the particles gain kinetic energy and move around more quickly. Therefore they collide more frequently and with more energy resulting in more successful collisions per second and therefore an increased rate of reaction.
a) how does concentration increase rate of reaction? a) As the concentration increases the particles become more crowded meaning their collisions occur more frequently and there are a greater number of successful collisions within a set period of time hence the overall rate of reaction increases.
a) how does Surface area increase rate of reaction? a) increasing the surface area exposes more particles to reactants making collisions more frequent and hence increasing the number of successful collisions within a period of time, increasing the rate of reaction.
a) how do catalysts increase rate of reaction? a) They lower the activation energy required to start the reaction/ allow it to take place, increasing the overall rate of reaction without being used up b) chemicals which are used in industry to lower the activation energy needed for a reaction to take place and increase rate of reaction without being used up
a) How does increasing the pressure affect rate of reaction? b) which phenomena is it similar to? a) Increasing the pressure is like increasing the concentration, it forces the reacting particles closer together meaning their collisions occur more frequently and there are a greater number of successful collisions within a set period of time so the rate of reaction increases
a) On a graph you know a reaction has stopped because? b) In a table you know a reaction has stopped because? a) The line becomes horizontal showing no more product is formed b) The numbers will stop changing/ increasing
a) How can rate of reaction be compared in a graph and a table? a) the steeper the gradient in a graph the higher the rate of reaction (using axis to calculate gradient for comparison) The greater the difference between 2 consecutive readings in a table the higher the rate of reaction.
a) what can combustible powders cause? a) explosions
a) why are powders highly explosive? (3) 1) They have a large surface area and can disperse throughout the air. Meaning more of their particles are exposed to oxygen so have a higher successful collision frequency, which makes any reaction which occurs from the energy of an initial spark extremely fast and powerful, generating a proportionally huge amount of product in a small amount of time. 2) When they react in large concentrations with oxygen a large volume of CO2 and water vapour is made, which causes high pressure and explosive destruction. 3) The extremely small mass of each particle when suspended in a cloud allows it to catch on fire which much less energy than bulk material (no thermal energy lost to conduction), whole cloud involved in the reaction instantly.
a) What 4 things are needed for a dust explosion? a) 1) combustible dust 2) Ignition source, flame/ spark 3) of dust in a cloud, dispersed in air 4) Presence of oxygen
a) Name any 3 combustible powders? a) sugar, flour, custard powder, sulfur, cocoa
a) how can you increase the surface area of a substance? a) break it up into smaller pieces, it will have the same mass as a block structure of the substance but it will have a greater rate of reaction.
a) why will a powdered form of a substance have a greater rate of reaction than a block form of a substance? a) because in a block form only the first layer of particles (on the surface) are exposed to reactants and able to react, while those underneath are unaffected and uninvolved with the reaction. However, in a powder many more particles are exposed to reactants at any one time, making particle collisions more frequent and hence increasing the number of successful collisions, resulting in product within a period of time, increasing the rate of reaction overall.
a) What does RFM stand for? b)why is it significant? c) Which number in the periodic table of elements gives the RFM of any particular element? a) Relative Formula mass b) RFM'S make element quantities comparable in terms of atom constituents c) the atomic mass number, (always the bigger of 2 numbers)
a) What is the relative formula mass of Ca(NO3)2 ? When RFM of Ca= 40, N=14 and O=16 a) Ca=40 N=14 x 2 O= 16 x 3 then x 2 40 + 28 + 96 = 164 RFM = 164
a) what is the principle of conservation of mass? b) what does it mean literally? a) The conservation of mass states that mass cannot be created or destroyed b) it means that the total mass of reactants equals the total mass of product,there must be the same number of atoms on one side of the equation as the other
a) how do you prove the conservation of mass? a) you find the RFM of substances on one side of the arrow ( RFM = number of atoms) and check its the same as that on the other side of the arrow. Remember RFM is the same as atomic number in the periodic table.
a) Prove the conservation of mass in this reaction? CuCo3 -> CuO + CO2 when Atomic masses are Cu = 64, C = 12, O = 16 a) left side: CuCo3 = CU= 64 C=12 O= 16 x 3, =48 altogether left side: 64 + 12 + 48 = 124 RFM Right side: CuO + CO2 Cu = 64 O= 16 + (16 x 2), =48 C= 12 altogether right side: 64 + 12 + 48 = 124, product contains same number of atoms as reactant, 124 ->124, proof of conservation of mass
a) If you had 124g of CUCO3 in the reaction CuCo3 -> CuO + CO2 how many grams of CuO would you make? a) 1) You need to work out the RFM of CuCo3 and the RFM of CuO CuCo3 = 124 RFM CuO = 80 RFM Then put them as a ratio: CuCo3 : CuO 124 : 80 Divide the grams used (124) by the RFM of CuCo3 (124) the to find the relationship, = 1 Then use the relationship and RFM of CuO to find how many grams should be made. 80 x 1 = 80, you would make 80 grams of CuO
a) If you had 24.8g of CUCO3 in the reaction CuCo3 -> CuO + CO2 how many grams of CuO2 would you make 1) find RFM of CuCo3 and CO2 RFM CuCO3 = 124 RFM CO2 = 44 Then put them as a ratio: CuCo3 : CO2 124 : 44 Divide the grams used of a substance by the RFM of the substance itself 24.8 divided by 124 = 0.2 relationship = 0.2 Then use the relationship and RFM of the substance you want to find the grams of (CO2, 44 RFM) 44 X O.2 = 8.8 grams
a) How do you Calculate percentage yield?
a) Show that mass is conserved in the reaction: ZnCO3 -> ZnO + CO2 if RFM of Zn = 65, C = 12 and O =16 left side: ZnCO3 = Zn= 65 C=12 O= 16 x 3, =48 altogether left side: 65 + 12 + 48 = 125 RFM Right side: ZnO + CO2 ZnO= Zn = 65, O= 16 CO2= C= 12, O2 = 2 x 16 = 32 altogether right side: 12 + 32 + 16 + 65 = 125, product contains same number of atoms as reactant 125 ->125, proof of conservation of mass
a) A soap manufacturer calculates the yield required to be 150 tonnes. However when the product is made only 147.6 tonnes have been produced. Calculate the percentage yield a) 147.6 divided by 150 x 100 = 98.4 % YIELD
a) In the reaction 2HgO -> 2Hg + O2 0.069g of O2 was formed at a percentage yield of 93. 2%, what was the theoretical / predicted yield? a) 0.069g divided by 93.2 x 100 0.074g was the predicted yield.
a) What is percentage yield? a) The relationship between the maximum mass of product which could be made in a reaction and the actual mass of product which was collected.
a) What is 'theoretical yield'? b) Why is this rarely / never achieved? (3) a) The maximum mass of product which can be made in a reaction b) Because firstly, it assumes ideal reaction conditions, such as standard temperature and pressure in order to ensure all reagents are involved in the reaction, this is not generally achieved due to heat transfers to container materials ect. Secondly, other reactions between chemicals might occur on the side, using the reagents available in production of unwanted products. Lastly, measuring or purification of reagents prior to the reaction, might result in a loss of reactants and a change to the amount of product you could actually generate.
a) Why do Industrial processes need / want to have a high percentage yield? a) so they can reduce the amount of reactants wasted in formation of unwanted product which is costly and unhelpful. So they can create a higher yield of wanted product from the same amount of reactants which is less expensive in costs of raw materials and energy ( than doing the reaction numerous times over to produce the same quantity).
a) How is atom economy calculated?
a) A company makes potassium nitrate for fertiliser and rocket propellant in fireworks. H2O is the waste product, what is the atom economy of the reaction: KOH + HNO3 -> KNO3 +H2O a) If H2O is the waste product then KNO3 must be the desired product 1) find the RFM of the reactant KOH? K= 39 , O= 16, H=1 39 + 16 + 1 = 56 2) find the RFM of the reactant HNO3? H= 1, N= 14, O= 16 x 3, 48 1 + 14 + 48 = 63 3) Total reactant RFM? 56 + 63 = 119 4) find the RFM of the useful product KNO3? K= 39, N= 14, O= 16 x 3, 48 39 + 14 +48 = 101 Atom economy? (101 divided by 119) x 100 = 84.9%
a) Iron ore can be reduced to iron using the reaction: Fe2O3 + 3CO -> 2Fe +3CO2 CO2 is the wasted product, what is the atom economy of this process? a) If CO2 is the waste product then 2Fe must be the desired product. 1) find the RFM of the reactant Fe2O3 ? Fe= 56 x 2, 112 , O= 16 x 3, 48 56 + 48 = 160 2) find the RFM of the reactant 3CO? C= 12 x 3, 36 , O = 16 x 3, 48 36 + 48 = 84 3) Total reactant RFM?160 + 84 = 244 4) find the RFM of the desired product 2Fe? Fe= 56 x 2, 112 Atom economy?(112 divided by 244) x 100 = 45.9%
a) Zinc oxide can be made by this reaction: ZnCO3 -> ZnO + CO2 CO2 is the waste product. ZnO is the desired product. Calculate the atom economy for this reaction. a) ZnO is the desired product. 1) Find the RFM of the reactant ZnCO3? Zn = 65 , C = 12, O = 16 x 3, 48 Total reactant RFM? 65 + 12 + 48 = 125 2) Find the RFM of the desired product? ZnO? Zn = 65, O = 16 3) Total desired product RFM? 65 + 16 = 81 Atom economy? (81 divided by 125) x 100 = 64.8 %
a) Why does Industry want the highest atom economy possible? a) To reduce production of unwanted products that will need to be disposed of, and add to the overall cost. To make the process greener and more sustainable meaning better use of the reactants so that less raw materials will need to be harvested to form the same quantity of product.
a) This is the reaction in which asprin ( C9H804 ) is made: C7H603 + C2H3OCl -> C9H8O4 +HCL what is the atom economy of making asprin? Aspirin, C9H804 is the desired product. 1) find the RFM of the reactant C7H6O3 ? C7= 12 x 7, 84, H= 1 x 6, 6, O= 16 x 3, 48 84 + 6 + 48 = 138 2) find the RFM of the reactant C2H3OCl? C= 12 x 2, 24 , H= 1x3, 3, O = 16 Cl = 35.5 24 + 3 + 16 +35.5 = 85.5 3) The total RFM of reactants? 85.5 + 138 = 216.5 4) find the RFM of the desired product C9H8O4? C= 12 x 9, 108, H= 1 X 8, 8, O= 16 X 4, 64 108 + 8 + 64 = 180 Atom economy?(180 divided by 216) x 100 = 83% AE
a) A reaction absorbs heat from its environment is? b) Give an example process? Why? c) Example of an object? a) endothermic b) breaking bonds, because it takes a lot of energy to overcome bond forces and destroy them c) coolpack
a) A reaction which gives out heat is? b) Give an example process? Why? c) Example of an object? a) exothermic b) Bond making, because more energy is released than absorbed c) anything burning
a) How do you decide if a reaction is endothermic or exothermic? a) you compare the amount of energy released, with the amount absorbed.
a) Diagrams can be used to represent bond energy changes, what would a diagram showing an overall exothermic reaction look like? 1) activation energy is low 2) curve bellow/ product line lower than reactant line shows that energy is released in making products not absorbed
a) Diagrams can be used to represent bond energy changes, what would a diagram showing an overall endothermic reaction look like? 1) High activation energy (high curve above reactant energy line) 2) product energy line above reactant line shows that energy is absorbed in making products.
a) Label the diagram and state which kind of reaction it shows? b) What is happening in each stage? b) In stg 1, activation energy is being absorbed for the reactants to separate atoms. In stg 2 bonds are being broken and further energy absorbed from enviroment
a) label the diagram and state which kind of reaction it shows? b) What is happening in each stage? b) In stg 1, activation energy is being absorbed for the reactants to separate atoms. In stg 2, atoms join to form new bonds and more energy is released (more than was needed for reaction to start)
a) How do you calculate the energy transferred by a fuel in j? a) energy transferred in J = mass of substance heated (grams) x specific heat capacity x temperature change in degrees Celsius. j = m x c x T
a) what is the specific heat capacity of water? b) how can you find the mass of burned fuel during an experiment? a) 4.2 J/g degrees Celsius b) measure the mass of the fuel before and after testing.
a) To find out the energy released by 1 gram of fuel? a) 1. measure the mass of 1 gram of fuel 2. pour 100 grams of water into a copper calorimeter (1cm 3 = 1g) 3. Heat the water with the burning fuel 4. measure the temperature rise 5. Repeat 3+ times and with different fuel vessels to ensure fair testing (and maintain the same distance from the flame to the calorimeter).
a) How is the energy released per gram of fuel calculated? a) Energy per gram= energy released in J divided by mass of fuel burnt in g.
a) How could you compare the energy released when different liquid fuels burn? a) for many different fuels 1. measure the mass of 1 gram of fuel 2. pour 100 grams of water into a copper calorimeter (1cm 3 = 1g) 3. Heat the water with the burning fuel 4. measure the temperature rise 5. Repeat 3 + times and with different fuel vessels to ensure fair testing (and maintain the same distance from the flame to the calorimeter). 6. Then plot as a graph the energy released over a period of time or calculate the energy given out per gram of fuel used and present findings side by side.
a) What is batch production in industry? a) Where higher quality products are made in a certain amount of time and with in a fixed amount made, in batches. The machines can be turned off easily and the product sold within date as there is rarely an excess of product made. The initial cost of starting up a batch production line is low but the work is labour intensive so can be very costly later on. It can also be an inefficient way of producing product as the product is not being produced all the time.
a) Give examples of products made in a batch process? (4) a) Products which need a high quality or have short lives or are not in constant need. 1) cloths- quality 2) drugs - quality, short life 3) alcohol- quality 4) food- short life
a) What are the advantages of batch production? (6) 1) Initially cheap to start up (in comparison to continuous production) 2.)machines can be turned off easily= can change production to a different product easily. 3) Ensures that products are not over stocked or an unsellable excess made 4) Allows quantities to be made which can be sold within a given time for products with short lives or easily managed. 5) Is flexible and can adapt to an increased need for a product by producing more frequent batches or multiple batches at the same time 6) Ensures the quality of the product is there
a) What are the disadvantages of batch production? (5) 1. It needs to be supervised so is labour intensive and expensive long term. 2. Product is not made around the clock so the process can be said to be inefficient as the line is not in use all the time 3. Time is needed for cleaning and remodelling the line if product production changes 4. The rate of production is very low and cannot really keep up with any increased demand for the product made 5. The manual work is more difficult than in continuous production (where there is basically none) and relies on skilled employees
a) What is the cycle of batch production? (5) a) 1. Put reactants into vessel 2. carry out reaction 3. filter off desired product 4. clean out vessel ready for next batch 5. repeat
a) What is continuous production in industry? a) Where a machine dominated factory makes a product constantly, through day and night often at a low quality and for high demand or materials in constant need. It is energy intensive but costs less to maintain than stop and start the process again. It is a very efficient process which reduces the production cost of a product dramaticallly
a) What are the advantages of continuous production? (4) a) 1. The process has very low up and running labour costs because it is largely automated, product cheaper 2. The process produces a large amount of product in a small amount of time and can supply a high demand. 3. The process is very efficient, it works day and night producing product. 4. It takes less energy to maintain as long as the machines work constantly and are not turned off and then back on
a) What are the disadvantages of continuous production? (4) a) 1. The process is either off or on and working constantly, meaning that it is extremely inefficient if not in constant use. 2. The initial cost of set up (building a specialised factory) is incredibly high 3. The process is inflexible, product production cannot easily change and decommission of factories would be incredibly expensive. 4. Relies heavily on predicted high continuous demand for a product, if demand drops then the factories become very vulnerable
a) Give examples of products made in a continuous process? (6) a) any product where there is a constant demand, quality is not a huge issue and the product does not have a short life. 1. Industrial alcohol 2. Glass 3. Aluminium 4. Petrol 5. Oil 6. Bricks
a) Why is it difficult to develop and test new medicines? (6) 1. Animals used in testing before human trials have different biology to humans + findings aren't always valid. 2.The necessary animals, equipment and scientists are expensive and costly for drug companies to supply for research. 3. It can take 10 years of research and testing to develop a new drug because most do not pass one of the trials + scientists have to start over again. 4. Each country has strict rules which drug companies must follow, limiting their means of testing and ingredients. 5. Raw materials are rare and often costly 6. Many raw materials are found in plants and difficult to extract.
a) Why are medicines so expensive? (5) Their price takes into account development costs: (1) 10 years of expensive research and testing to develop a new drug as most do not pass one of the trials 2. The raw material used in research and the drugs themselves are rare and expensive 3. The necessary animals, equipment and scientists, are costly for drug companies to supply for research. 4. The marketing + advertising campaigns when the drug is launched are expensive, yet necessary in order to find customers for the new drug 5. New compounds need to be made before the drug can be developed,this lengthens the process, making it more expensive and putting off the return profits from release.
a) What mass of carbon would you need to burn, in excess oxygen to make 84g of carbon dioxide? a) In excess oxygen= O2 to create CO2 + no carbon monoxide produced 1) write a symbol equation, work back from product? C + O2 -> CO2 2) find the number of atoms/ RFM? C + O2 -> CO2 12 + (16 X 2) -> 12 + (16 x 2) 44 -> 44 3) Work out the relationship between the grams of product made and the RFM of the product? 84 divided by 44 = 1.909 4) Use the relationship to find the grams of the reactant carbon (RFM 12). RFM X relationship, 12 x 1.9 = 22.9g
a) What does a graph of rate of reaction look like?
a) what is collision theory? b)How does collision theory explain rates of reactions a) Collision theory states that product is formed when reactant particles collide successfully, with enough energy to initiate in a reaction. b) Rate of reaction at different points in time can be explained by collision theory: the higher the frequency of collisions the more successful collisions there are within a period of time and the higher the rate of reaction or more product formed in relation to time.
a) How are chemicals extracted from plants? a) 1) Leaves are crushed to break the cell walls 2) They are boiled in a suitable solvent to dissolve the compounds 3) Chromatography is used to separate and identify individual compounds 4) The desired compound is isolated and purified, or multiple compounds are isolated and tested for potentially useful properties
a) What is chromatography? b) What is the difference between chromatography and thin layer chromatography? a) A method of separating mixtures of substances in solution (gas or liquid). b) Thin layer chromatography is similar to paper chromatography, but instead of paper, a thin layer of powder is coated onto a glass or plastic plate. Different powders and solvents are used, depending on the type of substance being separated.
a) How can the purity of certain compounds be tested? a) 1) Pure compounds have consistent boiling and melting points if a substance boils/ melts within a sensible range of the pure substance temperature then you can deduce it is fairly pure as it behaves similarly to the pure substance. 2) You can test the purity of substances through thin layer chromatography and comparison of the speed of movement of substance x with its known pure sample
a) Why is it difficult and costly to get a licence for a new drug? (6) a) Because a drug licence is only given when a dug performs effectively, when the side effects are known, and when it passes the trials. MEANING... 1) Thousands of compounds need to be tested to find effective compounds 2) Likely compounds need to be tested on living tissue to ensure safety 3) Long term trials on humans are needed to identify possible side effects 4) Many similar compounds need to be developed to reduce side effects 5) Recommended doses need to researched and shown to be effective 6) The research needs to be independently verified
a) What are Allotropes? b) Can you give an example? a) different structures of the same atom b) diamond, graphite and fullerenes are all allotropes of carbon.
a) What are Moles for? b) What is one mole equal to? a) They are a standard which can convert atomic mass into real terms and calculate the grams of a substance, knowing only the number of moles and the RFM. It allows chemists to make predictions about the masses of different substances that are involved in reactions. b) One mole of any element has a mass in grams that is equal to its relative atomic mass.
a) What are fullerenes? b) what can they be used for? c) give an example of a fullerene used in this way? a) Allotopes/ structures of carbon that form sphere or hollow tubes. b) 1. They can be used to carry drug molecules around the body and deliver them to where they are needed. 2. As well as trap dangerous molecules in the body and remove them c) Buckminsterfullerene
a) How many atoms are there in buckminsterfullerene? what kind are they? a) 60 carbon atoms
a) Diamond structure diagram
a) Graphite structure diagram
a) fullerenes structure for example buckminsterfullerene looks like this
a) What is the formula of buckminsterfullerene? b) what is each buckminsterfullerene structure measured in? a) C60 b) Nanometres (10 to the power of -9 metres long is one nanometre)
a) What are covalent bonds? b) what are the 2 types of covalently bonded substances? a) A shared pair of electrons between two + potentially different non metals b) simple molecules and giant covalent structures
a) What is the difference between simple covalent bond molecules and giant covalent structures/ macro covalent structures? a) Simple molecules conduct electricity in neither molten nor solid state as they do not contain any de-localised electrons free to flow and carry charge, they contain only a few atoms held together by covalent bonds and they have a low melting point due to the weak inter-molecular forces which break down easily. Giant covalent structures often conduct electricity in solid and liquid form because they often contain de-localised electrons free to carry charge, they also contain many many atoms held together by strong covalent bonds meaning huge amounts of energy are needed to break the bonds and they have a high melting point.
a) Why can't diamond conduct electricity when graphite, another allotrope of carbon can? a) Diamond cannot conduct electricity because despite its giant covalent structure there are no de-localised electrons free to flow and carry charge, where graphite has many elecrons between its covalent layers
a) How many particles are there in 1 mole of any atom? b) what is the formula triangle for mole to grams to RFM calculations? a) 6.02 x 10 to the power of 23 b)
a) What is the RFM of a compound that weighs 266g if i have 4.75 moles? b) Calculate the number of moles of carbon dioxide molecules in 22 g of CO2. a) 266 divided by 4.75 = mass 56 b) mass = 22g RFM = 12 + (16 x 2), RFM =44 mass divide by RFM 22 divided by 44 = 0.5, 0.5 moles
a) What would the mass of 2.5 moles of NH3 be? MOLES = 2.5 RFM= N=14 H= (1) x 3 = 3 RFM = 14 + 3 = 17 2.5 x 17 = 42.5g
a) What Kind of structure of carbon are diamond, fullerenes and graphite? b) Why is diamond used in drill bits? a) Giant covalent lattices/ structures. b) Because each carbon atom in a diamond has really strong covalent bonds in all directions joining it in a lattice- which makes it extremely hard and means large amounts of energy are needed to break the bonds and cause it to melt. This meaning it has a high melting point and is able to resist the damage which could occur from friction as well as the associated heat build up, without becoming molten or falling apart. In addition the imperfections which naturally occur in diamond form cleaving plates which allow them to be shaped and make them a good surface for cutting away material.
a) How are carbon atoms joined in diamonds? a) Every carbon atom is covalently bonded to four others in a three-dimensional tetrahedral lattice with all the outer shell electrons being shared. There are no de-localised electrons to carry flow.
a) Why is diamond used in Jewellery? a) Because the imperfections which occur in diamonds form cleaving plates which allow them to be shaped and give facets which reflect light.
a) What can graphite be used as? b) Why? a) Dry, high temperature lubricants and as a core in pencils. b) because graphite has strong covalent bonds which mean it has a high melting point, giving it resistance to melting at high temperatures and suitability as a high temperature lubricant. And because graphite has carbon atoms which are covalently bonded to three others in flat hexagonal layers, leaving one outer shell electron this structure gives graphite weak inter layer forces meaning layers can slide over each other and leave residue on paper.
a) what is the melting point of diamond? a) 3350 degrees Celsius.
a) what an you use as a catalyst system? a) Nano tubes b) because atoms of the catalyst can be attached to the large surface area on the nano tube in-order to speed up the reaction.
a) How are carbon atoms joined in graphite? a) Every carbon atom in graphite is covalently bonded to three others in flat hexagonal layers, making it extremely strong and giving it a high boiling point, this formation also leaves an unshared electron which gives weak interlayer attraction and means layers can slide over one another as lubricant or pencil core and results in de-localised electrons capable of carrying charge, so graphite can conduct electricity.
a) What does giant covalent bonding form? b) What will happen if a structure like this forms bonds in different directions or has de-localised electrons? c) What will happen if a structure like this forms bonds in layers? a) A compound with millions of very strong fixed bonds and a high melting point b) It will be hard like a diamond or it will have the ability to carry charge. c) It will be extremely strong horizontally but very week vertically, meaning it will be easy to cut into slices and the particles will slip as the layers slip over one another like in a pencil
a) What are the issues with Patents for drug manufacturers? a) - Often patents and rights to make the drug expire before the costs of researching and making the drug are recouped, meaning many other companies can develop that drug and there is no money in it any more.
a) What is nano-technology? b) How does sunscreen use nano-technology? a) The science of building tiny devices to solve challenges in medicine, electronics and defence b) Because sunscrean uses chemicals from white paint which are effective in absorbing Uv radiation to prevent damage to skin
a) How small is 'Nano' ? b) How do car airbags use nano-chemistry? a) IO-9 m ( the size of an atom) b) They are triggered by a sensor containing a capacitor formed of 2 opposite electrical charges. When the car decelerates suddenly the plates are pushed together, changing the capacitance. This change is detected by an external circuit which then activates the airbag.
a) What are the uses of nano-chemistry? (5) 1) Self cleaning windows 2) Car airbags 3) Diagnosis of illness in the body 4) Catalysts 5) Computer chips
a) What are the safety concerns of nano-technology?(4) b) Who would be most at risk of any potential dangers? c) how could the risks be reduced? 1) Nano- technology is free to move around in the body and so may have an increased potential of toxicity 2) they could be inhaled, ingested or absorbed through the skin and cause damage to cells 3) They have similar structures to asbestos fibres and so may cause respiratory problems. 4) Unknown science b) Researchers and scientists c) reduce workers setting to one of low exposure
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