Zusammenfassung der Ressource
Chemistry ATP
- Precautions
- For poisonous gases
(toxicity of gas)
- Fume cuboard
- Well ventilated room
- Prevents burning of a substance
- e.g. Nitrogen Dioxide,
Ammonia, Bromine
- Repeat and take
averages
- Wear goggles,
lab coat and
tie hair back
- When heating
alcohol, a water
bath should be
used because fire
will be produced if
touched by a
lighted splint
- Common Variables
- Concentration
- Volume
- Surface Area
- Mass
- Temperature
- Exam Technique
- Independent variable
(the one you change)
goes on x-axis and the
dependent on y-axis
- For manufacturing errors,
look carefully at apparatus
(e.g. burettes without taps)
- Don't round values in
titration or mole questions
- Tests
- For water
- Add anhydrous
Copper(II) Sulphate
(white to blue)
- Add anhydrous
Cobalt(II) Chloride
(blue to pink)
- For alkenes
and alkanes
- Alkenes: Add (if liquid) or pass through
(if gas) bromine water and
shake (brown to colourless)
- Alkanes: (remain orange/brown)
- For purity of
substance
- Test melting/boiling
point and compare to
correct value
- Cation/Anion
Tests (link)
Anlagen:
- For
hydrochloric
acid
- Add
silver
nitrate
(white
ppt.
formed)
- Gas Collection
- Upward
delivery
- Gases less
dense than
air
- e.g.
Hydrogen,
Ammonia
- Downward
delivery
- Gases more
dense than air
- e.g. Carbon Dioxide
- Displacement of
water method
- Insoluble gases
- e.g. Methane
- Experiments
- Crystallisation
- Heat till point of
crystallisation, allow to
cool slowly, filter and dry
- Place a stirring rod in
solution and if crystals
form on it, it's the
point of crystallisation
- Crystallisation is the formation
of solid crystals of a substance
by precipitating it out from a
staurated solution
- Fermentation
- Glucose and yeast
used (yeast contains
enzymes)
- 37 degrees is
optimum for
enzymes
- Reaction might stop due to an excess
in conc. of alcohol, the yeast dies or
Glucose finishes up
- Bung is used to let
Carbon Dioxide out and
prevent entry of Oxygen
- Oxygen would
oxidise the alcohol
to Carboxylic Acid
and affect anaerobic
respiration
- Chromotography
- Spray locating
agent if colourless
dye (such as
amino acids and
sugars)
- RF = distance
moved by
dye/distance
moved by solvent
- Electrolysis
- Concentration promotes the
discharge of ions further down the
reactivity series because their
compounds are stable
- Suitable electrodes:
Graphite/Carbon/Steel
- If on heating condensation
occurs, the solid is hydrated
- Agents
- Oxidising
- Acidified Potassium
Manganate(VII) (purple
to colourless)
- Acidified Potassium
Dichromate(VI) (orange
to green)
- Reducing
- All metals (mention
Group 1 when asked)
- Aqueous Potassium Iodide
(colourless to brown)
- Sulphur
Dioxide
- Drying
- Concentrated Sulphuric Acid (all gases except Ammonia)
- Calcium Oxide (for Ammonia and neutral gases)
- Anhydrous Calcium Chloride (all
gases except Ammonia)
- Locating
- Ninhydrin
- Universal Indicators
- Methyl orange (red, orange, yellow)
- Phenolphtalein (colourless, pink)
- Bromothymol (yellow, dark green, blue)
- Apparatus
- Condenser
- To liquify vapour in distillation
and returning unreacted
vapour back to the solution
- Glass beads
- To cool the gases in
fractional distillation
by absorbing heat
from them
- Fractionating
column
- To separate various liquids
using their boiling points
- Safety bulb
- In pipettes to prevent
liquid from entering
mouth
- Cover ethanol
with a lid because
it's volatile
- Crush a solid to increase surface
area (use a pestle and mortar)
- Purpose of
mineral wool is
to absorb and
hold liquid
- Colours
- Metals
- Zinc is a grey solid
(white compounds)
- Lead is a shiny
bluish metal
- Iron is a shiny
blackish solid
- Iron (II) salts are
grey-green. Iron (III) salts
are reddish-brown.
- Group 1, 2 metals are
white/silvery white
- Group 3 metals are shiny grey
- Copper is a pinkish solid
- Copper(II)
sulphate/hydroxide/nitrate
are blue. Copper(II)
chloride/carbonate are green.
- Non-metals
- Iodine is a black solid
- Its vapours are
purple. Silver
iodide and Lead
iodide are yellow.
- Chlorine is a
green gas
- Silver chloride
and Lead chloride
are white
- Bromine is a
red-brown gas
- Silver bromide
and Lead bromide
are cream
- Nitrogen dioxide
is a brown gas.
- Sulphur and
Phosphorus are
yellow solids
- Important reactions
- Metal + Water → Metal hydroxide + Hydrogen
Metal + Acid → Salt + Hydrogen
- Acid + Carbonate → Salt + Water + Carbon Dioxide
- Acid + Base → Salt + Water
- Metal Hydroxide + Ammonia Salts → Salt + Ammonia + Water
- Acidic Oxide + Water → Acid
Neutral Oxide + Air → Acid
Basic Oxide + Acid → Salt + Water
- Alkene + Steam → Alcohol
- Glucose + Yeast → Ethanol + Carbon Dioxide
- Acid + Alcohol → Ester + Water
- Alcohol (when oxidised) → Organic Acids + Water
- Potassium,
Sodium, Calcium,
react with water to
form hydroxides
and metals below
(till Copper) react
with steam to
form metal oxides
- Water and oxygen is needed for
rusting - water level increases as
oxygen is used up
- Copper oxide and
hydrogen make copper
(black to brown)
- Acids and Bases
- A concentrated acid contains a
large number of H+, hydrogen
ions and a concentrated base
contains a large number of
OH-, hydroxide ions
- A strong acid ionizes
completely giving H+ in
solutions and a strong base
ionizes completely gived OH-
in solutions