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chemistry
Topic 3 - chemical changes
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Created by
Oliver Sullivan
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Cards (20)
pH scale
Shows how
acidic
or
alkaline
a substance is
0-6
is acidic
7
is neutral
8-14
is alkaline
Alkali
Soluble
base
Can
neutralize
an acid
Dissociation
1.
Acids
split up into
hydrogen
ions (H+)
2.
Alkalis
split up into
hydroxide
ions (
OH-
)
Strong vs Weak acids/alkalis
Strong -
completely dissociate
Weak -
partially dissociate
Neutral pH
has equal concentrations of
H+
and
OH-
ions
Common acids
Hydrochloric
acid (HCl)
Nitric
acid (HNO3)
Sulfuric
acid (H2SO4)
Common alkalis
Sodium
hydroxide (NaOH)
Potassium
hydroxide (KOH)
Calcium
hydroxide (Ca(OH)2)
Indicator
Used to test if a substance is
acidic
or
alkaline
Methyl
orange
,
phenolphthalein
,
litmus
paper
,
universal
indicator
Testing for gases
1. Hydrogen -
squeaky
pop
with
lit
splint
2. Carbon dioxide -
bubbled
through, turns
limewater
cloudy
3. Oxygen - relights
glowing
splint
Neutralization
Reaction of an
acid
and
base
to form a
salt
and
water
Acid reactions
1. Acid + metal oxide/hydroxide =
salt
+
water
2. Acid + metal =
salt
+
hydrogen
3. Acid + metal carbonate =
salt
+
water
+ carbon dioxide
Salt
Product formed when an
acid
and
base
react
Solubility of salts
Soluble -
nitrates
, most chlorides, most
sulfates
Insoluble - silver/lead chlorides, lead/barium/calcium sulfates, most
carbonates
, most
hydroxides
Making copper sulfate
1. React copper
oxide
with
sulfuric
acid
2. Add
excess
copper oxide
3. Filter off
unreacted
copper oxide
4.
Crystallize
to get
pure
copper sulfate
Titration
Controlled
addition
of acid/base to determine
exact
amount needed
Electrolysis
Using
electricity
to split up
ionic
compounds
Electrolysis setup
1.
Positive
anode,
negative
cathode
2.
Ionic
compound as
electrolyte
(molten or dissolved)
Oxidation and Reduction
Oxidation
- loss of electrons at anode
Reduction
- gain of electrons at cathode
Electrolysis of dissolved ionic compounds
Less
reactive
ion is given off (e.g. hydrogen over sodium, chlorine over
hydroxide
)
Half
equations describe what happens to each
ion
during electrolysis