Class notes Science - preparation of salt & solubility

Chemistry
The preparation of the salt (sodium Chloride




(buffer) 1. measure 25cms of sodium hydroxide
Neutral
weak
Mak
Strong
acid Strongare
PH = 1 PH =
4 (Buffers PH = 13 (liquid) .




pale light light
Bromothymol yellow yellow green blue blue
2 .
Add drops of methyl orange indicator
Blue
Methyl orange Red Red orange orange orange
3 . Fill burette with hydrochloric acid


Phenolphthalein colourless colourless colourless
Pale
pink
Pale
pink
and then open tap .




Pale Pink pale
Blue litrus pale pink purple
dark
4 Scale is 0 on top and 50 bottom
purple purple
.




Pale Pale
Pale pink Pale pink Perple
Red Litmus purple purple .
5 Add acid from burette in small



portions. till
Continue yellow/orange colour


Making a soluble salt from an insoluble base disperses

.
6 Stop when you reach endpoint of titration

copper
copper oxide
+
+ sulfuric acid - >
sulfate water (only orange colour


CuO() +
H2SO4(aq) >
-
CuSOp(aq) +
H20()

To
get a pure salt


1. Add insoluble copper oxide to Sulfuric acid and Stir . Warm



I don't boil (experiment) with
-



gently Repeat 3 times


2
. Solution turns blue as the reaction occurs. indicator


find added
-


.
3 Filter the solution of acid
average amount


25cm3 of
-


solution in basin in Conical
4
. Gently heat the
evaporating alkali flask +




add average amount of acid



Making an insoluble salt-precipitation -Gently heat the solution in evaporation

basin


I dissolve any solids to make a
solution)
-

Remove of Liquid

leave
-


in warm place to crystalise

1 .
Mix the Liquids together -
a solid should appear


.
2 filter the residue with distilled water


3
. Leave in warm
dry place for water to evaporate




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