The rate and extent of chemical change

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  • Created by: leo1223
  • Created on: 29-05-18 16:01
What is the equation for the rate of reaction?
Rate of reaction = Amount of reactant used or product formed / time
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What is meant by the 'activation energy'?
The activation is the minimum amount of energy required to cause a reaction
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What four factors affect the rate of reaction?
Temperature, surface area, catalysts and concentration
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Describe the effect temperature has on a reaction and it's rate of reaction?
In a reaction the temperature affects the rate at which particles move and collide. A higher/lower temperature causes particles to collide more/less often and with greater/less energy, which gives a high/low rate of reaction
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Describe the effect concentration has on a reaction and it's rate of reaction?
In a reaction the concentration affects the proximity of particles. At a high/low concentration the particles are close to/far away from each other, which causes more/less frequent collisions, which means the rate of reaction increases/decreases
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What effect does pressure have on the rate of reaction of reacting gases?
Increasing the pressure of reacting gases also increases the frequency of collision, decreasing the pressure has the opposite effect
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Describe the effect surface area has on a reaction and it's rate of reaction?
In a reaction the surface area of the reactants is where particles collide and react. When there is a large/small surface area more/less particles are available for collisions, so more/less collisions take place and a faster/slower reaction occurs
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Describe the effect a catalyst has on a reaction and it's rate of reaction?
In a reaction a catalyst reduces the amount of energy needed for a successful collision, therefore making more collisions successful which in turn speeds up the rate of reaction. A catalyst also offers a surface for molecules to attach to
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What is a catalyst?
A catalyst is a substance that increases the rate of reaction without being used up in the process
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What catalyst is needed for the cracking of hydrocarbons?
Broken pottery
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What catalyst is needed for the production of ammonia?
Iron
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Why are catalysts important for industrial processes?
Catalysts are important as they increase the rate of reaction which subsequently reduces the overall cost of many industrial processes as not as much energy is required after the addition of a catalyst
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How can the direction of a reversible reactions be changed?
By changing the conditions, i.e. temperature, concentration and pressure
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What is meant by a 'closed system'?
In a closed system, no reactants are added and no products are removed
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What happens when a reversible reaction occurs in a closed system?
When a reversible reaction occurs in a closed system, an equilibrium is achieved when the rate of the forward reaction is equal to the rate of the backwards reaction
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What is Le Chatelier's principle?
Le chatelier's principle states that if a system in equilibrium is subjected to a change in conditions, then the system will shift to resist the change
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What happens to a exothermic reaction when temperature is changed?
In an exothermic reaction when temperature increases, yield decreases, In a exothermic reaction when temperature decreases, yield increases
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What happens to a endothermic reaction when temperature is changed?
In an exothermic reaction when temperature increases, yield increases. In an endothermic reaction when temperature decreases, yield decreases
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What happens in a reversible reaction that involves gases when pressure is changed?
In a reversible reaction with gases present, an increase in pressure favours the reaction that produces the least number of gas molecules, where as a decrease in pressure favours the reaction that produces the most number of gas molecules
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What happens in a reversible reaction when the concentration of one of the reactants or products is changed?
When a reversible reaction is affected by a change in concentration, it is no longer in equilibrium, the system shifts to one side of the reaction until it can reach equilibrium once more
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What happens in a reversible reaction when the concentration of the reactants is increased?
In a reversible reaction when the concentration of the reactants is increased, the position of equilibrium shifts so that more products are formed until the equilibrium can be reached again
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What happens in a reversible reaction when the concentration of the reactants is decreased?
In a reversible reaction when the concentration of the reactants is decreased, the position of equilibrium shifts so that more reactants are formed until the equilibrium can be reached again
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Card 2

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What is meant by the 'activation energy'?

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The activation is the minimum amount of energy required to cause a reaction

Card 3

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What four factors affect the rate of reaction?

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Card 4

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Describe the effect temperature has on a reaction and it's rate of reaction?

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Card 5

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Describe the effect concentration has on a reaction and it's rate of reaction?

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