•(iii) The basic oxides react with the impurities in the
iron and form a slag. What information in the diagram suggests
that the slag is less dense than the molten iron? [1]
–
–
•(iv)
Which one of the following is a basic oxide? Put a ring around the correct answer.
•calcium
oxide carbon dioxide sulphur dioxide water [1]
•(v)
Why is steel rather than iron used for constructing buildings and bridges? [1]
–(e)
Special steels contain added elements such as vanadium, chromium, cobalt
or nickel. These are all transition metals.