c6 rate of reaction Flashcards
reactions can go at all sorts of different rates
-rate of chemical reaction is how fast the REACTANTS are CHANGED into PRODUCTS.
-one of the SLOWEST is the rusting of iron .
-other slow reactions include CHEMICAL WEATHERING -
acid rain damage to limestone buildings.
-example of MODERATE SPEED reaction would be the metal MAGNESIUM reacting with an ACID to produce a gentle stream of bubbles.
-BURNING is a FAST reaction, but EXPLOSIONS are even FASTER and release a lot of gas.
-explosive reactions are all over in a FRACTION OF A SECOND.
you need to understand graphs for the rate of reaction
-you can find the speed of a reaction by recording the
amount of PRODUCT FORMED, or the amount of REACTANT USED UP over TIME.
-the STEEPER the line on the graph, the FASTER the rate of reaction. OVER TIME the line becomes LESS STEEP as the reactants are USED UP.
-the QUICKEST REACTIONS have the STEEPEST lines and become FLAT in the LEAST TIME.
particles must collide with enough energy in order to react
- reaction rates are explained perfectly by collision theory.
- rate of chemical reaction depends to:
- the COLLISION FREQUENCY of reacting particles. more collisions the faster the reaction is.
- the energy TRANSFERRED during a collision. particles have to collide with ENOUGH ENERGY for collision to be successful.
- minimum amount of energy that particles need to react to is called the ACTIVATION ENERGY.
- need this much of energy to BREAK THE BONDS in the reactants and start reaction.
factors affecting the rate of reaction
- more collisions increases the rate of reaction.
- increasing the temperature increases the rate
- increasing the concentration of pressure increases the rate
- increasing the surface area
- using a catalyst.
what is a catalyst? and example of biological catalysts
a substance which speeds up chemical reactions without being used up.
-enzymes catalyse reactions in living things.
