Exam Qs Flashcards
Permanent hard water can be softened.
Explain how adding sodium carbonate (Na2CO3) softens permanent hard water.
the sodium carbonate / carbonate ions react with calcium / magnesium ions, forming a precipitate of calcium carbonate / magnesium carbonate
therefore the water is softened because this removes the calcium / magnesium ions, which cause hardness, from the water
In terms of of bond energies, explain why hydrogen can be used as a fuel
hydrogen can be used as a fuel because when it reacts with oxygen more energy is released in bond making than used in bond breaking therefore the reaction releases energy or the reaction is exothermic
In terms of electronic structures, explain why iodine is less reactive than bromide
iodine is less reactive than bromine because the iodine (atom) is bigger or outer electrons (level / shell) further from the nucleus
therefore the forces attracting an incoming electron are weaker or there is more shielding of the forces attracting an incoming electron therefore the outer electron gained less easily
When is equilibrium achieved?
an equilibrium is achieved when rate of the forward reaction is exactly the same as the rate of the backward reaction
How is Ethanoic acid formed
From a reaction between ethanoic acid and oxygen _ oxidation
