Rates of Reactions
- Created by: Katie
- Created on: 21-05-13 16:58
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- Rates of reactions
- Collision Theory
- An explanation of chemical reactions in terms of reacting particles colliding with sufficient energy and the correct orientation for a reaction to take place.
- Activation energy
- The minimum amount of energy needed to start a reaction.
- The affect of concentration
- As you increase the concentrationthe rate is quicker.
- Higher concentration= particles closer together
- It also increases the frequency of collisions so the rate of a reaction increases.
- The graph would like somehing like: the line startig half way up the y axis and then going in a steady diagonal line up.
- Real life example - in limestone when the statues are damages by acid rain. The higher the concentrationof acid in the rain water, the quicker the damage occurs.
- Increasing the concentrationof reactants in solutions increases the frequency of collisions between particles and so it increases the rates of reactions.
- The affect of surface area
- The larger the surface area, the more frequent collisions will take place, so there is a faster rate.
- Real-life example - When you light a fire, you use small pieces of wood to begin the fire to increase the surface area. This means ther is more wood exposed to react with the oxygen.
- The rate of a chemical reaction increases if the surface area of any solid reactant is incresed. This increases the fequency of collisions between reacting particles.
- The affect of temperature
- The higher the temperature the greater the kinetic energy of the particles. Therefore, they are more likely to collide. Collisions will have more energy, causing the rate to increase.
- Real-life example - Fridge/freezer slows down the rate of food going off.
- Graph would look like: a stright digonal line going up from the point 0.
- Reactions happen quicker as the temperature increases. Increasing the temperature increases the rate of the reaction because particles collide more frequently and more energetically. More of the collisions result in a reaction because a higher proportion of particles have energy greater than the activatin energy.
- Collision Theory
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