C3 A-C

C3 A-C

1. C3 A - Rates of reaction

   • Interpolation: Making an estimate between ranges
   • Extrapolation: Making estimates beyond the range of results (predicting)
   • Fast reaction means a short reaction time
   • Long reaction means a slow reaction time
   • We calculate the speed of a reaction from a graph by measuring the gradient (steepness of the slope)
     • To calculate the gradient we use the formula: How much you made dived by how long it took

2. C3 B - Concentration, Temperature, Particle size and Pressure.

   • As the temperature increases, the reactant particles have more kinetic energy and so the particles are moving around faster. This leads to more frequent successful collisions.
   • Reactions occur when particles collide together with sufficient energy to react.
   • Concentration is the measure of how many particles are in 1L of water.
   • Concentration can be lowered by adding more water to the solution, which makes it more diluted.
   • The higher the concentration the faster the reaction time. As the concentration increases there are more reactant particles in the same volume. This leads to more frequent successful collisions
   • Smaller particles will have a faster rate of reaction because there will be more collisions per second.
   • Acid can hit the outer layer of atoms but not the atoms in the center.
   • Explosions are reactions that occur rapidly and release large volumes of gas.
   • Increasing the pressure increases the rate of reaction because there are more collisions per second.

3. C3 C - Catalysts

   • A substance added to a chemical reaction to make it go faster
   • Copper powder is the catalyst for the reaction between zinc and sulfuric acid.
   • Alminium oxide in the cracking of long chain hydrocarbons
   • Does not make more collisions per second
   • When added to a reaction the same amount of product is made but in a much shorter time
   • Specific to the reaction
   • Enzymes are the catalyst in the human body