Chemistry - The Laws of Conservation of Mass

Practise Questions

1. When a log burns in a fire, the ashes have a much lower mass than the log. Explain.
As the wood burns, it is releasing carbon dioxide (and if incompletely burning carbon monoxide). The stuff left behind is carbon (which didn't get enough oxygen to convert it completely to carbon dioxide, and any other minerals or high-burning organics that might have have been in the log.

2. A solid has a mass of 35 g. When it is mixed with a solution, a chemical reaction…