Rates, concentration and pressure
The greater the rate or frequency of A collision between reactant particles that has enough energy for a reaction to happen., the greater the rate of reaction. If the The concentration of a solution tells us how much of a substance is dissolved in water. The higher the concentration, the more particles of the substance are present. of a reacting Mixture formed by a solute and a solvent. or the Force exerted over an area. The greater the pressure, the greater the force exerted over the same area. of a reacting gas is increased:
- the A substance that reacts together with another substance to form products during a chemical reaction.A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules. become more crowded
- the frequency of collisions between reactant particles increases
- the rate of reaction increases
Note that the mean The capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow. of the particles does not change. However, since the frequency of collisions increases, the frequency of successful collisions also increases.
Graphs
The rates of two or more reactions can be compared using a graph of mass or volume of A substance formed in a chemical reaction. formed against time. The graph shows this for two reactions.
The Another word for steepness. On a graph, the gradient is defined as being the change in the 'y' value divided by the change in the 'x' value. It defines how steep a line is. of the line is equal to the rate of reaction. The faster reaction at the higher concentration or pressure:
- gives a steeper line
- finishes sooner