Reaction with Metals - general

1
Reaction with Metals - general

• Many metals react with acids to form a salt and
  hydrogen gas.
• The general word equation is

metal acid ? a salt hydrogen

• The salt will depend upon the metal and the acid
  used.

• Hydrochloric acid gives metal chlorides
• Sulphuric acid gives metal sulphates
• Nitric acid gives metal nitrates

• So, for example

hydrogen

magnesium chloride
?
hydrochloricacid

magnesium
2
Evidence of Reaction
Some of these reactions show bubbles being
produced. These are bubbles of hydrogen gas. This
proves that a reaction is taking place because a
new substance is forming. How do we test for
hydrogen?
Oxygen in the air
hydrogen
Mg acid
3
Activity

• Use the general equation to finish of the word
  equations below

metal acid ? a salt hydrogen
magnesium sulphuric acid ?
magnesium sulphate
hydrogen
iron nitric acid ?
iron nitrate
hydrogen
calcium sulphuric acid ?
calcium sulphate
hydrogen
Zinc hydrochloric ?
acid
zinc chloride
hydrogen
4
React with Metals Metal Reactivity

• We can use the activity series of metals to
  predict how vigorously (if at all) a metal will
  react.
• The more reactive the metal, the more vigorous
  the reaction.
• The least reactive metals do not react at all.

• Which metal fits the description silver
  potassium iron
• Explodes in acid
• Bubbles slowly in warm acid
• Doesnt react

potassium
iron
silver
5
Formula of salts

• Chemists often use formula equations to show not
  just what atoms are present but also how many.
• To do this we need to understand what the numbers
  in a formula represent. Here are some examples.

Name of Salt
Contains
Formula
sodium chloride
one Cl
one Na
NaCl
magnesium chloride
two Cl
one Mg
MgCl2
potassium nitrate
three O
one N
one K
KNO3
potassium sulphate
four O
one S
two K
K2SO4
calcium nitrate
six O
two N
one Ca
Ca(NO3)2
6
Activity

• How many of each type of atom does the formula of
  the salt represent?

Name of Salt Formula Contains Contains Contains
calcium chloride CaCl2 Ca Cl
sodium sulphate Na2SO4 Na S O
magnesium sulphate MgSO4 Mg S O
magnesium nitrate Mg(NO3)2 Mg N O
calcium sulphate CaSO4 Ca S O
one
two
two
one
four
one
one
four
two
one
six
one
one
four
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Formula Equations

• Step 1 Write down the word equation.
• Step 2 Replace words with the chemical formula .
  (You will be given or need to look up the formula
  at this stage.)
• Step 3 Check that there are equal numbers of
  each type of atom on both sides of the equation.
  If not, then balance the equation by using more
  than one.
• E.g. The reaction of magnesium with hydrochloric
  acid

magnesium hydrochloric acid ? magnesium chloride hydrogen
Mg HCl ? MgCl2 H2
Neither H nor Cl balance.Need 2 HCl
Mg 2HCl ? MgCl2 H2
8
Activity

• Can you finish off the equations below
• Step 1 Write down the word equation.
• Step 2 Replace words with the chemical
  formula.
• Step 3 Balance the type of atom on both sides.

magnesium sulphuric acid ? magnesium sulphate hydrogen
Mg H2SO4 ? MgSO4 H2
Already balances No change
potassium sulphuric acid ? potassium sulphate hydrogen
K H2SO4 ? K2SO4 H2
Need 2 K on both sides
2K H2SO4 ? K2SO4 H2
9
Metals with Hydrochloric Acid
hydrogen

magnesium chloride
Mg HCl ? MgCl2 H2
2
No reaction
2
Cu HCl ? - -
hydrogen

aluminium chloride
Al HCl ? AlCl3 H2
3
2
2
6
hydrogen

calcium chloride
Ca HCl ? CaCl2 H2
2
10
Metals with sulphuric and nitric Acid
hydrogen

zinc sulphate
?
Zn H2SO4 ? ZnSO4 H2
hydrogen

magnesium nitrate
Mg HNO3 ? Mg(NO3)2 H2
2
hydrogen

iron nitrate
Fe HNO3 ? Fe(NO3)3 H2
3
6
2
2
hydrogen

calcium sulphate
Ca H2SO4 ? CaSO4 H2
?
11
Metal oxides and acids
Metal oxide acid ? a salt water

• Most metal oxides are not soluble.
• i.e. They are bases but not alkalis. This means
  they are often slower and may need heating to
  make them react

water

copper sulphate
12
Metal oxides and acids
Metal oxide acid ? a salt water
water

zinc sulphate
ZnO H2SO4 ? ZnSO4 H2O
water

sodium chloride
Na2O 2HCl ? 2NaCl H2O
water

iron nitrate
Fe2O3 3HNO3 ? Fe(NO3)3 3H2O
13
Metal carbonates and acids
Metal carbonate acid ? a salt
water carbon dioxide

• When metal carbonates react with acids they fizz
  giving off carbon dioxide gas.
• Most metal carbonates are not very soluble and so
  reactions may be slow.

water

calcium chloride
carbon dioxide

14
Metal carbonates and acids
Metal carbonate acid ? a salt water
carbon dioxide
water

zinc sulphate
?
sulphuric acid

carbon dioxide
ZnCO3 H2SO4 ? ZnSO4 H2O CO2
water

sodium chloride
?
hydrochloric acid

carbon dioxide
Na2CO3 2HCl ? 2NaCl H2O CO2
water

nickel nitrate
?
nitric acid

carbon dioxide
NiCO3 2HNO3 ? Ni(NO3)2 H2O CO2
15

• Which of these is NOT a typical property of
  metals?
• conduct
• strong
• dense
• brittle

16

• What is the symbol for Gold?
• Go
• Au
• Ag
• au

17

• Which of the following elements is not a metal?
• copper
• lead
• lithium
• neon

18

• Which of these is a salt?
• Sodium carbonate
• Sodium chloride
• Sodium hydroxide
• Sodium

19

• Which of these do all acids contain?
• Hydrogen
• Sulphur
• Oxygen
• Nitrogen

20

• Which of these salts might be formed from nitric
  acid?
• Potassium chloride
• Sodium nitride
• Aluminium sulphate
• Calcium nitrate

21

• Which of these metals might not react with hot
  dilute acid?
• Sodium
• Calcium
• Silver
• Iron

22

• Which of these substances would not neutralise an
  acid?
• Silver nitrate
• Sodium carbonate
• Calcium oxide
• Magnesium hydroxide

23

• What number must replace X to balance the
  equation?
• Fe(OH)3 X HCl ? 3H2O FeCl3
• 1
• 2
• 3
• 4

24

• What number must replace X to balance the
  equation?
• CaCO3 X H2SO4 ? H2O CaSO4 CO2
• 1
• 2
• 3
• 4