Question

When a piece of paper or wood is burned, you are left with ashes that seem to weigh less than the paper or wood before it was burned. Yet when a substance is burned, it is oxidized and therefore must weigh more than it did before it was burned. Explain what happened to the “missing” weight.

Answer 1

The ashes of the wood or paper either got blown around in the wind because of the ashes being so small and weightless, or they went into the air around you.

Answer 2

It just got blowed or you can say get mixed in the air around you. You can see tiny pieces of ash while buring paper or wood. And that's exactly your answer.