Answer:
The danger in igniting the Bunsen burner was that cellulose is a highly flammable organic compound, and its combustion reaction would result in a fire or explosion. The chemical properties and behaviors that support this response include cellulose being a complex carbohydrate made up of long chains of glucose units, which are highly reactive and readily burn in the presence of oxygen and heat.
A balanced chemical equation for the combustion of cellulose is:
C6H10O5 + 6O2 -> 6CO2 + 5H2O
If Gary weighed out 5 grams of cellulose and then sneezed as he carried the cellulose through the lab, the amount of carbon dioxide produced from the reaction would be approximately 30 grams (6 moles x 5 grams/mole = 30 grams). This assumes that all of the cellulose was burned completely in a balanced reaction and that the products were able to escape from the reaction vessel.