Rate of reaction, reversible reactions and dynamic equilibrium GapFill

The speed of a reaction is called its rate of reaction. This can be calculated by dividing the amount of a reactant used, or the amount of a  gasmixturesolutionproductcatalystside-product formed, by the time taken for the reaction to occur. The amount can be the volume, the  surface areamasspressureconcentrationrelative formula massdensity or the number of moles. Graphs of amount against time are usually  disconnectedoscillatingS-shapedstraightZ-shapedcurved lines. A straight line which touches the curve at only one point is called  a constant linea line of best fita tangenta rate linea gradientan asymptote.

Multiple factors can affect the rate of a general reaction:

• the  fizzinessmassvolumeconcentrationsurface areatransparency of the solution or the  entropyflammabilityvolatilitypressurecolouropacity of a gas
• the presence of  an acidan oxidising agenta catalystanother reactanta flameoxygen
• the  melting pointflammabilityconductivitymasshardnesssurface area of any solid reactant
• the temperature

 ConcentrationActivationCatalystCollisionMoleReaction theory can be used to explain how factors affect reaction rate. Higher concentrations or pressures lead to more  conservativepre-determinedenergeticfrequentunsuccessfulweak collisions, and increasing the temperature increases collision frequency and the  efficiencysizeconcentrationsurface areapressureenergy of the collisions. A catalyst provides a different reaction pathway with a lower  rateactivation energyenergy changepressuresurface-area-to-volume ratiotemperature.

Reversible reactions are reactions in which the products can react to form the reactants. They are represented using a  »←«<⇌→. Reversible reactions that are exothermic in one direction are  staticunfeasiblejust as exothermicendothermicneutraleven more exothermic in the other direction. When the rate of the forward reaction and the rate of the backward reaction are equal, the reaction is  fastat dynamic equilibriumstoppedcompleteunstableslowing.