1. Uses of Metal Objective: to understand the uses of metals in industry
To understand how to optimise the efficacy of metals using alloys.

2. What is an alloy?
An alloy is a mixture of a metal with at least one other element.
Steel is a common example of an alloy. It contains iron mixed with carbon and other elements. Adding other elements to a metal changes its structure and so changes its properties.
The final alloy may have very different properties to the original metal.
By changing the amount of each element in an alloy, material scientists can custom-make alloys to fit a given job.
Photo credit: © 2007 Jupiterimages Corporation.

3. Why is steel stronger than iron?
The atoms in pure iron are arranged in densely-packed layers. These layers can slide over each other. This makes pure iron a very soft material.
The atoms of other elements are different sizes. When other elements are added to iron, their atoms distort the regular structure of the iron atoms.
It is more difficult for the layers of iron atoms in steel to slide over each other and so this alloy is stronger than pure iron.

4. What types of steel are there?
Steel can contain up to 2% carbon.
Varying the amount of carbon gives steel different properties. For example, a higher carbon content makes a hard steel.
Different types of steel are classified
by how much carbon they contain.
low carbon steel contains less than 0.25% carbon
high carbon steel contains more than 0.5% carbon.
Two other important types of steel are:
stainless steel – an alloy of iron that contains at least
11% chromium and smaller amounts of nickel and carbon
titanium steel – an alloy of iron and titanium.

5. Reactivity of Metals
IGCSE Chemisty

6. Now you try Try to react each of the metals with water.
If they don’t react, try with warm water.
Place each of the following metals in a small dish of hydrochloric acid
If it doesn’t react try again with warm acid.
Fill in your table to show what happens
Metal
Potassium
Sodium
Reaction with HCl
Magnesium
Copper
Zinc
Iron

7. Investigating reactivity with water (I)
It was investigated how reactive some metals are when they react with water and made these observations:
lithium
Metal
Reaction with water
sodium
potassium
Bubbles of gas are given off quite quickly. When tested with universal indicator the water is now alkaline.
The sodium melts and skims over the surface producing a stream of small bubbles. Sometimes a yellow-orange flame appears.
Potassium immediately produces a lilac flame as it skims around the surface making a fizzing noise.
Which of these metals is the most reactive with water?
Which of these metals is the least reactive with water?

8. Products of metals reacting with acid
Metals react with acid producing bubbles of gas.
The “squeaky pop” test shows that this gas is hydrogen.
When a metal reacts with acid, the products are a metal salt and hydrogen.
What is the general equation for the reaction of a metal with acid?
How does the type of acid affect the type of salt produced?
metal
acid
metal salt
hydrogen + 

9. Metals and hydrochloric acid – equations
Can you complete the word equation for each reaction?
hydrochloric
acid
magnesium
chloride
hydrogen +
magnesium + 
hydrochloric
acid
aluminium chloride
hydrogen +
aluminium + 
hydrochloric
acid
zinc
chloride
hydrogen +
zinc + 

10. Metals and sulfuric acid – equations
Can you complete the word equation for each reaction?
sulfuric
acid
magnesium
sulfate
hydrogen +
magnesium + 
sulfuric
acid
aluminium
sulfate
hydrogen +
aluminium + 
sulfuric
acid
zinc
sulfate
hydrogen +
zinc + 

11. Metals and nitric acid – equations
Can you complete the word equation for each reaction?
magnesium
nitrate
hydrogen +
magnesium +
nitric acid 
aluminium
nitrate
hydrogen +
aluminium +
nitric acid 
zinc
nitrate
hydrogen +
zinc +
nitric acid 

12. Now you try Try to react each of the metals with water.
If they don’t react, try with warm water.
Place each of the following metals in a small dish of hydrochloric acid
If it doesn’t react try again with warm acid.
Fill in your table to show what happens
Metal
Potassium
Sodium
Reaction with HCl
Magnesium
Copper
Zinc
Iron

13. copper potassium zinc magnesium sodium iron
Based on the results from all your experiments can you list the following metals from most reactive to least reactive?
copper
potassium
Most reactive
Potassium
Sodium
Magnesium
Zinc
Iron
Copper
zinc
magnesium
sodium
Least reactive
iron