Would lighting a candle in a glass jar create a partial vacuum?
Yes it will create a partial vacuum. The candle was will burn in the available oxygen and the two main products of combustion will be carbon di oxide which remains as a gas, and water vapour which will either be absorbed into the remaining gas in the jar or will condense out as moisture on the inner surface of the jar. After a short while the free oxygen will be burned and the candle flame will go out, but the gaseous products of combustion will less than the original oxygen volume and a partial vacuum will be created.
