Science Revision Cards; 0.0 / 5 ? ScienceChemistryGCSEOCR Created by: Lauraa01Created on: 03-12-13 17:20 What does 'rate of reaction' measure? Rate of reaction measures how much product is formed in a fixed period of time. 1 of 23 What can the 'rate of reaction' be worked out from? Rate of reaction can be worked out from the gradient of a graph. 2 of 23 How do you work out the gradient of a graph? Gradient = y / x 3 of 23 What is a limiting reactant? A limiting reactant is a chemical used up in a reaction that limits the amount of product formed. 4 of 23 When do reactions occur? Reactions occur when particles collide together. 5 of 23 What does the rate of reaction depend on? Rate of reactions depend on the number of collisions between the reacting particles. 6 of 23 What can increase the rate of reaction? Rate of reaction can be increased by increasing the concentration or raising the temperature or pressure. 7 of 23 What needs to happen for a successful collision to occur? For a successful collision to occur, each particle must have enough energy to react. 8 of 23 What do catalysts change? Catalysts change the rate of reaction. 9 of 23 What is mass conserved in? Mass is conserved in a chemical reaction as the reactants become products 10 of 23 Why does the atom economy need to be high? The atom economy needs to be as high as possible to reduce unwanted products. 11 of 23 Why does the percentage yield need to be high? Percentage yield needs to be as high as possible to reduce reactant waste and cost. 12 of 23 How do you work out Percentage Yield? Percentage Yield = Actual Yield / Predicted Yield x 100 13 of 23 How do you work out Atom Economy? Atom Economy = Mr of desired products / Sum of Mr of all products x 100 14 of 23 What is bond breaking? Bond breaking is endothermic process. 15 of 23 What is bond making? Bond making is an exothermic process. 16 of 23 How do you work out how much energy is transferred? Energy transferred (J) = mass in water heated (g) x specific heat capacity of water x temperature change ('C) 17 of 23 How do you work out the amount of energy per gram? Energy per gram = Energy released (J) / Mass of fuel burnt (g) 18 of 23 What are continuous processes used to make? Continuous processes are used to make chemicals such as ammonia. 19 of 23 What are batch processes used to make? Batch processes are used to make pharmaceutical drugs. 20 of 23 How are chemicals extracted from plants? Chemicals are extracted from plants by crushing, boiling, dissolving and chromatography. 21 of 23 Name three things which are allotropes of Carbon. Diamond, graphite and fullerenes are allotropes of carbon. 22 of 23 Why can graphite conduct electricity? Graphite can conduct electricity because it has electrons that can move between layers. 23 of 23
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