reactions

• what happens when elements react ?

  they combine with other atoms to form compounds
• carbon and oxygen react what is the product word and symbol?


  carbon dioxide CO2
• write out the symbol for calcium hydroxide?

  ca(OH)2 with hydroxide brakets are needed because otherwise there would only be 2 hydrogrens
• balance the equation Fe + Cl*2 -> FeCl*3 ?

  2Fe + 3Cl*2 -> 2FeCl*3
• hydrogen and oxygen are formed in a reaction where water splits apart 1)what is the word equation 2)what is the symbol equation ?

  1)water -> hydrogen + oxygen 2) H*2O -> H + 2O
• what is a salt ?

  the product of reaction between acid and base
• what is a displacement reaction ?


  A chemical reaction where one element is replaced by another element in a compound.
• give the balanced symbol equation for the displacement reaction between bromine and sodium iodide ?

  2NaI + Br2 -> 2NaBr + I2
• what is the equation for concentration?

  concentration(g/dm^3) = mass of solute (g)/ volume of solvent (dm ^3)
• whats a solute ?


  A solute is a substance that is dissolved in a solvent to form a solution.
• what is a solvent ?

  A substance capable of dissolving other substances.
• what is a solution ?

  A solution is a homogeneous mixture of two or more substances, where one substance (the solute) is dissolved in another substance (the solvent).
• what is oxidation ?

  Loss of electrons. or gain of oxygen
• what is reduction ?

  gain of electrons or loss of oxygen
• 2Fe2O3 + 3C -> ?

  4Fe + 3CO2
• what is an exothermic reaction ?

  A reaction that releases heat.
• what is an endothermic reaction ?

  A reaction that absorbs heat from its surroundings.
• give 3 examples of an exothermic reaction 


  combustion, nuetralisation, hand warmers, oxidation
• give 2 examples of endothermic reaction

  sports injury pack, thermal decomposition
• what does a graph of an exothermic reaction look like ?

  like this

  A) x

  
• what does a graph of an endothermic reaction look like ?

  like this

  
• what happens to bonds in an endo thermic reaction when energy is supplied ?

  they break
• what happens in terms of bonds in anexothermic reaction ?

  bonds are formed and energy is released
• energy must be supplied to break bonds what kind of reaction is bond breaking ?

  Endothermic
• energy is released when new bonds are formed what kind of reaction is bond forming ?

  Exothermic
• what does a rate of reaction graph look like whats on the x and y axis and what does the flat line on a rate of reaction graph tell us ?

  flat line = reaction has finished

  
• what 4 things affect the rate of reaction ?

  concentration of reactants (pressure of gas) , temperature, presence of a catalyst and surface area
• what must particles do in order to react ?

  collide
• what is the equation for rate of reaction ?


  Rate of reaction = amount of reactant used or product formed/Time
• hydro carbon + oxygen -> ?

  carbon dioxide +water
• what are the products of complete combustion ?

  Carbon dioxide and water.
• what are the three possible products of incomplete combustion ?

  Carbon monoxide ,soot(Carbon) and unburnt fuels.