OCR Gateway C3 4.5 / 5 based on 5 ratings ? ChemistryEnergy of reactions/Exothermic and endothermic reactionsRate of reactionC3GCSEOCR Created by: elliesykes2000Created on: 15-04-16 17:33 What is a limiting factor? The reactant that is completely used up when the reaction is over 1 of 34 What factors affect the rate of reaction? Concentration, temperature, and surface area 2 of 34 Why does increasing the concentration increase the rate of reaction? There are more particles in a given volume available for collisions 3 of 34 Why does increasing the temperature increase the reaction rate? The particles gain kinetic energy and are moving faster so there is more likely to be a successful reaction 4 of 34 Why does increasing the surface area increase the reaction rate? There are more particles exposed and available for collision 5 of 34 Why do catalysts speed up the reaction rate? They lower the activation energy and provide a surface for reactions to take part on 6 of 34 What is conservation of mass? The mass of the products is equal to the mass of the reactants 7 of 34 What is the percentage yield? The amount of product you make as a % of the amount you theoretically make 8 of 34 Why don't most reactions have a yield of 100%? Raw materials may not be pure, some product may be left in the apparatus, and the reaction may not have completely finished, 9 of 34 How do you work out atom economy? (Mass of useful product/mass of all products) x 100 10 of 34 What are the problems with low atom economy? Lots of waste - expensive to remove and dispose of, uses resources quickly, raw materials are expensive 11 of 34 How do you calculate energy transferred? mass of water x 4.2 x temperature change 12 of 34 How do you calculate energy transferred per gram of fuel? energy transferred/mass of fuel used 13 of 34 Does an exothermic reaction give out or take in energy? Give out 14 of 34 Does an endothermic reaction give out or take in energy? Take in 15 of 34 What is an energy value of a bond? The energy that is taken in to make that bond or given out when breaking that bond 16 of 34 How are batch products made? In small amounts to meet demand 17 of 34 What is a disadvantage of batch processes? High labour costs and not as efficiant 18 of 34 How are continuous products made? 24/7 production and constantly working at full capacity 19 of 34 What is a disadvantage of continuous processes? Not flexible 20 of 34 How are medicines made? Batch process 21 of 34 Why are medicines so expensive? Labour costs, research and testing, raw materials, marketing and legal costs, development time, energy costs 22 of 34 Why is developing new drugs so expensive? Thousands of compounds need to be tested on living tissue and long-term trials need to prove effective 23 of 34 How can you tell if a chemical is pure? It will melt and boil at a fixed temperature and it will give the same result when tested using chromatography 24 of 34 What is an allotrope? A different structure of the same element. they have different physical properties but similar chemical properties 25 of 34 What is graphite used for? Pencils 26 of 34 What is the structure of graphite? Layers with a delocalised electron that moves along the layer. layers are only weakly attracted 27 of 34 What are the properties of graphite? High melting and boiling points, conducts electricity 28 of 34 What is diamond used for? Jewellery and cutting tools 29 of 34 What is the structure of diamond? Strong covalent bonds with no delocalised electrons 30 of 34 What are the properties of diamond? Hard, high melting and boiling points, doesn't conduct electricity 31 of 34 What is buckminsterfullerene used for? To carry and deliver drug molecules around the body 32 of 34 What is the formula for buckminsterfullerene? C60 33 of 34 What are nanotubes? They are fullerenes that can be used to reinforce graphite, transport drugs around the body, or as semi-conductors in electrical circuits 34 of 34
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