pract Flashcards
always wash used equipment w/ deionised
if ask add Barium Chloride
same, Barium Nitrate test
- nitric acid + barium nitrate
- hydrochloric acid + barium chloride
MUST ADD SAME ANION ACID FOR ACIDIFICATION
prevent contamination
if smth not given in pract, means…
NO NEED THIS!!
i.e. no limewater = no carbon dioxide gas
powder given
hydrogen/co2/o2 test?
Carbonate
Co2 Test
silvery/shiny
hydrogen/co2/o2 test?
hydrogen test
acidify
hydrogen/co2/o2 test?
co2 test
generic solution S given
hydrogen/co2/o2 test?
co2
add (soln.) Slowly
add few drops
add (soln.) until no further change, seen
add in excess
1/2 test tube
when anything involve H2O2
must do what?
hydrogen peroxide
test o2
no change
no visible change
for every action done in pract, there is…
1 observation
what to note down when filtering
appearance filtrate, residue
what to write down for pract
- hot/cold
- gas is pungent (ONLY smell in pract, chlorine//ammonia)
- colour
- mixture dissolve, _ solution
- no change observed
observation when co2/o2/h2 gas released
think about their characteristics
colourless, odorless gas produced
amend all mistakes
light blue ppt
soluble in excess
light blue ppt formed
soluble in excess Aq ammonia to give dark blue soln.
which gas have to write efferverscence produced
ALL gas
even chlorine gas e.g.
how to determine identity of salt/carbonate
- soluble/insoluble (SPAN)
- what have you added alr?
1 e.g. no ppt other than blue ppt observed therefore indicate presence, G1 ions
2 (i.e. if you add sodium hydroxide -> R, cannot say R contain sodium chloride as you have added the ion into R)
how desc metal (s)
shiny GREY solid
except Cu (brown solid)
SHINY IS NOT A COLOUR
even g1 lolol coz when u cut it as shiny as iron. dark part is oxidised (rusted) part.
copper(II) colour
red-brown
how desc non-transition metal compound (aq)
colourless soln.
main determiner of colour is still compound // element
wat 2 look out for (heating)
- condensation
- test gas
- colour change
rust/corrosion of metals
difference, similarity
rust -> cnfm bad
corrode -> may be good
both req water, oxygen
temperature to what sf/dp
1dp
why use styrofoam/polystyrene cup in reactions?
- reduce heat loss to surroundings
how to measure rate of reaction of smth that give out gas?
- measure volume of gas
- in fixed time interval
pract how draw stopwatch
MUST LABEL
page 21
https://docs.google.com/document/d/1Ep_FO9CxYSFbxmf3Zqg9mgm9NNyt2enpfMDr49gufrU/edit?tab=t.0
h2o2 reaction
catalyst
h2o2 (reversible) h2o + o2
Manganese Oxide / Copper Oxide
catalyst take part in chem reaction;
but chemically unchanged
recommended amt of
mass
volume of liquid
conc. of soln.
making experiment
mass (1-5g)
vol, liquid (10-50cm^3)
conc, soln. (0.5-2mol/dm^3)
how u know reaction stop
when effervescence stopped
when added solns…/leave to stand
- no visible change when ___ added
- when left to stand, soln turn from __ -> __
colour of sand-like colour
pale brown
