# CHEMISTRY - rates of reaction

Rates of Reaction
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Methods of Measuring Rates of Reaction
1. measure the decreasing mass of the reaction mixture - 2. measure the increasing volume of gas given off - 3. measure the decreasing light passing through a solution
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The Collision Theory
"reactions can only happen if particles collide with enough energy to change into new substances" - increasing temperature, concentration, pressure and surface area will increase the rate of collision and therefore the ROR
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Activation Energy
the mimimum energy required for particles to react
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Energy and Reversible Reactions
a reaction that is exothermic in one direction must be endothermic in the other - the amount of energy released by the exothermic reaction exactly equals the amount taken in by the endothermic reaction
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Closed System
no reactants or products can escape - so an equilibrium is reacted
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Equilibrium in Reversible Reactions
where the rate of the forwards reaction is equal to the rate of the backwards reaction - here, both reactions happen but the amounts and products remain constant
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Le Chatelier's Principle
"when you change the conditions in a system at equilibrium, the position of the equilibrium shifts to cancel out the change" - however, if there are equal numbers of mollecules on either side, changing the pressure will make no difference
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## Other cards in this set

### Card 2

#### Front

1. measure the decreasing mass of the reaction mixture - 2. measure the increasing volume of gas given off - 3. measure the decreasing light passing through a solution

#### Back

Methods of Measuring Rates of Reaction

### Card 3

#### Front

"reactions can only happen if particles collide with enough energy to change into new substances" - increasing temperature, concentration, pressure and surface area will increase the rate of collision and therefore the ROR

### Card 4

#### Front

the mimimum energy required for particles to react

### Card 5

#### Front

a reaction that is exothermic in one direction must be endothermic in the other - the amount of energy released by the exothermic reaction exactly equals the amount taken in by the endothermic reaction