Criado por cab.boyle13
mais de 9 anos atrás
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Questão | Responda |
RATE OF REACTION | The rate of reaction measures the amount of product made in a specific time. It can be increased by: Raising the temperature Increasing the concentration Increasing the pressure |
TEMPERATURE OF REACTANTS | LOW TEMPERATURE: The particles move slowly - the particles collide less often and at lower energy - rate of reaction is slow HIGH TEMPERATURE: The particles move fast - particles collide more often and at higher energy - rate of reaction is fast |
WHAT ARE THE THREE FORMS OF CARBON? | Diamond Graphite Buckminster fullerene (buckyballs) |
DIAMOND | Is insoluble in water and doesn't conduct electricity (no free electrons) Colourless, clear and lustrous Very hard and has a very high melting point - large amount of covalent bonds Giant molecular structure |
GRAPHITE | Has a layered structure Insoluble Black and slippery Lustrous and opaque Conducts electricity - it has delocalised electrons High melting point - strong covalent bonds |
BUCKMINSTER FULLERENE | Known as a 'buckyball' Is made of 60 carbon atoms (C60) It is a black solid |
NANOTUBES | Nanotubes can be made by joining fullerenes together. Nanotubes conduct electricity and are very strong. Uses: Reinforce tennis racket frames, develop more efficient industrial catalysts |
WHAT IS ATOM ECONOMY? | Atom economy is a way of measuring the number of atoms that are wasted in a chemical reaction. If all the atoms in the reactants are in the product the atom economy is 100% Atom economy = Mr of products x 100 Sum of Mr of all products |
PERCENTAGE YIELD: 100% yield - no product has been lost 0% yield - no product has been made | Percentage yield = Actual yield Predicted yield x100 Percentage yield is a way of comparing the amount of product made with the amount of product expected to make . |
BATCH PROCESS | In a batch process, reactants are put into a reactor and the product is removed at the end of the reaction. Batch processes: Make a product on demand on a small scale, can be used to make a variety of products, are labour intensive |
CONTINUOUS PROCESS | In a continuous process, reactants are continually fed into the reactor as the products are removed. Continuous processes: Make a product on a large scale, are dedicated to making just one product, operate all the time, run automatically |
EXOTHERMIC AND ENDOTHERMIC REACTIONS | EXOTHERMIC: Reactions release energy to the surroundings and cause a temperature rise ENDOTHERMIC: Reactions absorb energy from the surroundings and causes a temperature to drop. |
CATALYST | A catalyst is a substance that changes the rate of reaction without being used up. Activation energy is the energy needed to break the bonds of atoms for a reaction. A catalyst lowers the activation energy to speed up the reaction. |
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