Acids and Alkalis
Name_____________________
Universal Indicator and the pH scale
Universal Indicator changes colour depending on whether it is
in an acid, alkali or neutral solution.
1
2
3
Stomach acid
4
5
6
Lemon juice
7
8
9
10
11
12 13 14
Water Soap Baking powder Oven cleaner
Below 7 is
_____
Above 7 is
_________
Exactly 7 is
_________
Quiz on acids and alkalis
Acid, alkali or both???
1) This has pH of less than 7 ____________
2) This is often used in cleaners or soap __________
3) This would turn Universal Indicator red ________
4) Sodium hydroxide is an ____________
5) This would feel soapy on your skin _________
6) This could burn your skin _________
7) This will turn universal indicator purple _________
8) Lemon juice and vinegar are examples of weak _______
9) limewater (calcium hydroxide) is an example of this__________
Answers
acid
alkali
acid
alkali
alkali
both
alkali
acid
alkali
Neutralisation
An acid and alkali will cancel each other out (neutralise) each
other if the correct amounts are used
Acid + alkali
Salt + water
E.g. hydrochloric acid + sodium hydroxide
sodium chloride + water
This reaction is called ________________ because the
acid is used up and _________ is made.
Choose your answers from the list below:
combustion
respiration
neutralisation
hydrogen
water
oxygen
Names of salts
The name of a salt depends on the acid and
the alkali that are used to make it.
The first part of the name of the salt comes from the
alkali. Sodium hydroxide reacts with acids to make
salts that start with sodium.
The second part of the name of the salt comes from
the acid. Hydrochloric acid makes salts that end with
chloride.
Naming salts 2
Hydrochloric acid makes salts that end with chloride.
Sulphuric acid makes salts that end with sulphate.
Nitric acid makes salts that end with nitrate.
Adding sodium hydroxide to nitric acid will make water
and a salt called sodium nitrate.
sodium hydroxide + nitric acid
water + sodium nitrate.
Complete the blanks spaces
Adding sodium hydroxide to hydrochloric acid will make
water and a salt called sodium _________.
Adding sodium hydroxide to nitric acid will make water and
a salt called sodium _________.
Adding potassium hydroxide to sulphuric acid will make
water and a salt called _________ _________.
Adding magnesium hydroxide to hydrochloric acid will make
water and a salt called _________ _________.
Adding lithium hydroxide to sulphuric acid will make water
and a salt called _________ _________.
Answers
chloride
nitrate
potassium sulphate
magnesium chloride
lithium sulphate
Adding acid to carbonates
Carbonates are compounds containing carbon and oxygen.
When an acid and a carbonate are added together, the
mixture starts to fizz. A gas called _________ _________
is produced.
The limewater
will go
__________
What else is made????
You know that carbon dioxide is made when an acid
reacts with a carbonate. Two other new substances
are made as well. A salt is made and so is water.
metal carbonate + acid
carbon dioxide + salt + water
This reaction is called ________________ because the
acid is used up and _________ is made.
The name of a salt depends on the acid and the carbonate.
Adding calcium carbonate to hydrochloric acid will make a
salt called calcium chloride.
calcium
carbonate
+ hydrochloric
acid
carbon + calcium + water
dioxide
chloride
Complete the blanks spaces 2
Adding sodium carbonate to hydrochloric acid will make carbon dioxide,
water and a salt called _________ _________.
Adding sodium carbonate to nitric acid will make carbon dioxide, water
and a salt called __________ _________.
Adding potassium carbonate to sulphuric acid will make carbon dioxide,
water and a salt called ___________ _________.
Adding magnesium carbonate to hydrochloric acid will make carbon
dioxide, water and a salt called ___________ _________.
Adding copper carbonate to sulphuric acid will make carbon dioxide,
water and a salt called _________ _________.
Answers
sodium chloride
sodium nitrate
potassium sulphate
magnesium chloride
copper sulphate
Uses of acid reactions
When acids react new chemicals called salts are made.
These salts have many uses.
Sodium chloride is the chemical name
for table salt that we put on our chips.
Salts that are made from nitric acid contain
nitrate. Nitrates are needed by plants to
help them grow. Chemical companies use
nitric acid to make nitrate salts for farmers
to use as fertilisers for their crops.
Nitrate salts are also used in explosives.
Useful acid-alkali reactions
1) Hydrochloric acid is used in the stomach
to help digest food. If we eat too many
“rich” foods our stomachs make too much
______. This is called _____________.
Indigestion tablets take away this pain
because they ______________ the acid.
2) Soil is often acidic, mainly due to acid ____. This can
have bad effects on ______ and vegetable growth.
________ is an alkali that farmers and gardners add to
soil to _________ the acid.
Words – plant, indigestion, neutralise,
rain, acid, neutralise, lime
Reactions of metals with acids
When a metal reacts with an acid a gas called ______________ is
made. A salt is also made at the same time.
METAL + ACID
SALT + ____________
The name of the salt depends on the metal and the acid.
e.g. magnesium + hydrochloric acid
magnesium chloride + hydrogen
Complete the following reactions:
Calcium + hydrochloric acid
_________ ________ + __________
Zinc + hydrochloric acid
_________ ________ + __________
Iron + nitric acid
_________ ________ + __________
Lithium + sulphuric acid
_________ ________ + __________
These reactions are not neutralisation because _________
is not being made.
Testing for hydrogen
“POP”
Testing for hydrogen:
Hydrogen will make a
_______ splint go _______
Testing for salts
If a salt is present we will
see it when we evaporate
the water.
Acid gases
The names of three acid gases are:
_________ _________
_________ _________
_________ _________
When fossil fuels like coal, _____ or natural _____
are burned in power stations, the carbon contained
in them reacts with oxygen to form ___________
dioxide gas. Carbon dioxide also comes out of car
exhausts.
A car engine needs a spark to set the petrol on fire. The energy from the
spark makes nitrogen and oxygen join together to make the acid gas
called__________ dioxide gas.
Some fossil fuels contain sulphur. When the
fuel burns, the acid gas called
_________dioxide is made.
Problems with acid gases
The acid gases called _________
dioxide, _________ dioxide and
_______ dioxide dissolve in cloud
droplets and fall as _____
______.
The acid rain gets into
rivers and streams and
kills ______. It can kill
______ when it falls
onto their leaves.
Acid rain can also damage stone
buildings and metal structures
because it reacts and eats them away.