Conservation of Mass

Part 1: Answer to the splint question "Where did the mass go?"
Learn about combustion as a chemical reaction here: Combustion of Wood (simplified)

Here's another simple version: Combustion in general terms

Be aware, smoke is not a gas, but a mixture of gases, solids and water vapour. 



Part 2: Law of Conservation of Mass

Read about it here: Thoughtco Conservation of Mass (website)

Watch it here: Conservation of Mass Ted-Ed

Take down some key ideas in your book

Extension Ideas:

Conservation of Mass in Nature (Nature website)

What about Black Holes? A forum with some interesting ideas.