acids. + alkali Flashcards
acids
proton donors
release H+ ions in aq solutions
eg HCL, H2SO4
Bases
proton acceptors
want to get the H+ ions
neutralise acids.
soluble in water = aka alkali
alkali
soluble base that release OH- ions in aq solution
eg NaOH
strong acids
completely dissociate when dissolved in water
weak acids
partial dissociate when dissolved in water
salt =
formed when H+ ion of acid replaced by metal ion / ammonium ion
acid + base =
salt + water
acid + carbonate (metal CO3) =
salt + water + carbon dioxide
observations: effervescence due to co2
metal + acid
metal oxide + acid
metal hydroxide + acid
metal carbonate + acid
metal salt+ hydrogen
titrations method
*rinse equipment (burette with acid, pipette with alkali, conical
flask with distilled water)
1. measure out alkali using pipette into flask along with some indicator e.g., phenolphthalein
2. fill burette with acid
take an initial reading to see how much acid is in burette then add acid to alkali swirling each time stop when decolourised- record final reading from burette
3. now accurate titration = run acid within 2cm£ of end point then add acid dropwise.
4. work out amount of acid used to neutralise alkali
final - start reading= titre
*repeats titration until at least 2 concordant results are obtained- two readings within 0.1 of each other
phenolpthalein
pink = colourless
methyl orange
yellow to red
theoretical yield
mass of product that should be made if no chemicals lost
percentage yield =
actual/theoretical x100
theoretical
moles x MR of desired
atom economy
measure of proportion of reactant atoms that become part of desired product
= MR of desired/ sum of all (x100)
low atom economy = lots of waste
