Chemical reactions

Chemical reaction: a change that results in the formation that results in the formation of a new substance

Example of a word equasion

Iron + sulfur => iron sulfide

Example of a chemical equation

Fe + S => FeS

Law on conversion of mass

Antoine Lavoisier performed an experiment to investigate if the mass of the reachtants would be different to the mass of the products after a chemical reaction took place

What happened?

Lavoisier concluded that mercury reacted with oxygen inside a jar to produce mercuric oxide

==2==Hg + O2 => ==2==HgO

According to the law of conservation of mass there is no change in mass when a physical or chemical change occurs

Rate of reaction

Factors that effect rate of reaction:

  1. [[Types of reactants[[
  2. ]]Particle size]]
  3. {{Concentration{{
  4. }}Temperature}}
  5. <<Catalysts<<
Formula

Change in concentration of any one product or reactant

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Time taken

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[[1. Type of reactant[[

The rate of reaction depends on the types of chemicals that are reacting together

  • Magnesium reacts quickly with hydrochloric acid
  • Zinc reacts slowly with hydrochloric acid
]]2. Particle size]]

If a particle is smaller it has a larger surface area

{{3. Concentration{{

Concentration: amount per unit volume

The rate of reaction depends on concentration

The greater the concentration, the faster the rate

}}4. Temperature}}

The rate of reaction depends on temperature

The higher the temperature => the faster the rate

<<5. Catalysts<<

Catalyst: a substance that speeds up a chemical reaction, or lowers the temperature or pressure needed to start one, without itself being consumed during the reaction

The rate of reaction is altered by the presence of a catalyst

Rates of biochemical reactions

Biochemical reaction: a chemical reaction that takes place in living cells that is a reaction where new substances are formed

Examples of biochemical reactions
  • Cellular respiration
  • Photosynthesis
  • Digestion
Rates of chemical reactions are effected by:
  1. [[Concentration[[

   Concentration of enzymes and of the substances which the enzymes are acting. The general name given to the substance on which an enzyme acts acts is the substrate

  1. ]]Temperature]]

   Many biochemical reactions only take place at specific temperatures

  1. {{pH{{

   Many enzymes only work within specific pH ranges. Outside these pH ranges these enzymes become inactive