The magnesium was chopped up into short lengths and placed in a crucible with a lid which had been weighed.

The crucible, lid and magnesium was weighed again and then heated strongly.

The lid of the crucible was raised every few minutes.

When the reaction was over the apparatus was allowed to cool and then reweighed. All results were noted.

Results:

Mass of empty crucible + lid = 19.65 g

Mass of crucible, lid + magnesium = 21.11 g

What mass of magnesium was used:?     21.11-19.65 =     1.46g

By how much did the magnesium gain in mass?    21.17-21.11=    0.06g

Why did the magnesium gain in mass?   The magnesium gained in mass because it combined with oxygen from the air

Why did the crucible need a lid ?   To stop the smoke escaping

Why was the lid raised every few minutes?  To let air into the crucible so that the magnesium had oxygen

How can you tell when the reaction is over?   The reaction is over when the magnesium stops glowing

What chemical is left behind in the crucible?   magnesium oxide

What is the word equation for the reaction which takes place when the magnesium burns.

magnesium + oxygen    ---> magnesium oxide