Zinc reacts with oxygen from the air to form zinc oxide.
A student carries out an investigation to determine the mass of zinc oxide formed when a known mass of zinc reacts completely with oxygen.
This is the method the student used.
Step 1 Find the mass of an empty crucible and lid. Step 2 Put a known mass of zinc powder into the crucible and put the lid on. Step 3 Heat the crucible strongly for five minutes using a roaring Bunsen burner flame, lifting the lid occasionally. Step 4 Let the crucible, lid, and contents cool down. Step 5 Find the final mass of the crucible, lid, and contents.
Explain how the student could check that the zinc had reacted completely with oxygen.
