chemistry c5

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  • Created by: Emily
  • Created on: 05-06-13 17:53
what is a mole?
amount of a substance in a chemical reaction
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what is the relative atomic mass of an element?
the average mass of the atoms of that element
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during a chemical reaction no mass is lost nor gained, it's conserved, but the mass measured at the end may be..
greater if a gas has been gained from the air, or less if water vapour or a gas had been allowed to escape
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how can the empirical formula of a compound be calculated?
the percentage composition of the compound by mass or the mass of each element in the compound
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describe a dilute and concentrated solution..
concentrated- solute particles are more crowded together than in a dilute solution
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how do you convert a volume?
from cm3 into dm3 divide by 1000-, dm3 into cm3 multiply by 1000
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what are the two common units of concentration?
mol/dm3 and g/dm3
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what is the reaction called when an acid and alkali react together?
a neutralisation reaction
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what is a titration?
a method used to find the concentration of an acid/alkali
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what is an indicator?
they change colour depending on whether they are acidic or alkali solutions
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what kind of pH do acids and alkali's have?
acid- low pH when an alkali is added pH increases, alkali- high pH when an acid is added to it pH decreases
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what appuratus can you use to collect/measure the volume of a gas made in a reaction?
an upturned measuring cylinder, a gas syringe or an upturned burette
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what is the reactant that gets used up first called?
the limiting reactent
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what does it mean if you have lots of reactant particles?
there will be a greater number of collisions taking place
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what is equilibrium?
a reversible reaction can reach this (balance) the rate of forward reaction is equal to the rate of the backward reaction
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how can the position of the equilibrium be altered?
temperature, pressure, and concentration of reactants/products
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what happens if the position of equilibrium is to the right and what happens when it's to the left?
right- concentration of products is greater than the reactants and when it's to the right it's the other way around
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state a few uses of sulfuric acid..
paints/pigments, soaps/detergents, fibers, plastics and fertilisers
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describe the contact process..
1 sulfur is burned in a furnace to make sulfur dioxide 2 sulfur dioxide combines with oxygen from air in reversible reaction to make sulfur trioxide 3 sulfur trioxide is dissolved in water to make sulfuring acid
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how can equilibrium be moved to the left and right..
right- adding more reactant/removing product as it's made left- opposite
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what would a high pressure do to equilibrium?
push it to the right and increase the yeild
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what does increasing the temp do to the rate of reaction?
it increases it, but reduces the yield and pushes equilibrium to the left, a comprimise temp is used at 450c to get a balance between yield and rate
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what is a strong acid and a weak acid?
strong- ionises completely in water weak- partially ionises in water- reversible makes an equilibrium mixturr
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explain how a precipitate is formed..
insoluble solid is made by mixing 2 ionic solutions
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what does ethanoic acid or hydrochloric acid react with?
magnesium to produce hydrogen gas and calcium csarbonate to produce carbon dioxide gas
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what chemical is used to detect sulfate ions?
barium nitrate
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why does hydrochloric acid react faster than ethanol acid?
it's a stronger acid, greater concentration, higher frequency collisions
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why is a strong acid a better conductor than the same concentration than the same concentration of a weak acid?
fewer hydrogen ions in ethanoic acid to carry the charge
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what electrode, in electrolysis, is hydrogen gas made at?
negative
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what method can be used to make an insoluble compound?
mix the reactant solutions, filter off the precipitate, wash the residue in filter funnel with a bit of distilled water and dry the residue in an oven at 50c
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how can you detect halide ions?
silver nitrate- chlorides form a white precipitate, bromides form a cream precipitate. iodides- yellow precipitate
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how can you detect sulfate ions?
by using barium chloride- white precipitate is formed
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are precipitation reactions fast or slow?
very fast reaction between ions
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Other cards in this set

Card 2

Front

what is the relative atomic mass of an element?

Back

the average mass of the atoms of that element

Card 3

Front

during a chemical reaction no mass is lost nor gained, it's conserved, but the mass measured at the end may be..

Back

Preview of the front of card 3

Card 4

Front

how can the empirical formula of a compound be calculated?

Back

Preview of the front of card 4

Card 5

Front

describe a dilute and concentrated solution..

Back

Preview of the front of card 5
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