Chemical Reactions

A change that results in the formation of one or more new substances

One where no new substance is formed eg cutting paper

Chemicals that react together in a chemical reaction

The chemicals that are produced in a chemical reaction

Iron + sulfur = iron sulfide Fe + S = FeS

When a chemical reaction occurs, the total mass of the reactants is always equal to the total mass of the products

Melt ice cubes in a container with a lid and measure mass on an electronic balance No change

Sodium chloride solution in a comical flask • place a test tube with silver nitrate solution inside carefully, suspended by thread • rubber hung placed on comical flask • measure mass • shake comical flask so that it mixes • new white cloudy substance formed • measure mass : no change

The change in concentration per unit time of any one reactant or product

A substance that alters the rate of a chemical reaction by speeding it up or slowing it down but is not used up in the reaction Eg manganese dioxide

Type of reactants (nature of reactants) Particle size Concentration Temperature Catalyst

Magnesium and hydrochloric acid = hydrogen Zinc and hydrochloric acid = hydrogen Comical flask with magnesium and dilute hydrochloric acid , with a rubber bung and a tube leading out to an upside down graduated cylinder standing in a basin of water. Have a stopwatch. Measure volume of hydrogen (the water in the graduated cylinder will go down ) Same for zinc, draw graph Magnesium is faster than zinc

Calcium carbonate (marble chips) + hydrochloric acid Measure mass of graduated cylinder w acid inside, comical flask w marble child inside, and cotton wool to prevent spray escaping Cotton wool only allows carbon dioxide to escape - we will study the loss in mass Have a stopwatch , pour the acid in and record the loss in mass as it reacts Repeat with diff size marble chips

Same setup as the one for type of reactants , magnesium + diff concentrations of hydrochloric acid = hydrogen Have a stopwatch

Same setup as nature of reactants Magnesium + hydrochloric acid = hydrogen Different temperatures of hydrochloric acid 20,40,60

Same setup as nature of reactants Dilute Hydrogen peroxide in comical flask , with manganese dioxide (catalyst) . Rubber bung. Measure volume of oxygen at regular time intervals

Burns with a pop when mixed with air

Turns limewater milky Extinguished a lighted splint

Rekindled a glowing wooden splint

A chemical reaction that takes place in living cells , where new substances are formed

Biological catalysts

Concentration of enzymes and substrate • temperature • ph

Enzyme catalase which speeds up rate at which hydrogen peroxide is broken down in our bodies