Question

answer these two fast please ok ​

Answer 1

Answer:

➡️substance with constant chemical composition throughout its mass.

➡️burning of wood.

Explanation:

hope it helps you ✌️✌️

Answer 2

7. (b) A substance with constant chemical composition throughout its mass.

Pure substances are defined as substances that are made of only one type of atom or molecule.

$\rule{250}{2}$

8. (a) burning of wood

Burning is a non-reversible chemical change. When you burn wood, the carbon in the wood reacts with oxygen in the air to create ash and smoke, and energy in the form of light and heat. This is a permanent change that cannot be undone – you cannot turn ashes back into wood.