Answer: B
Explanation: I answered randomly
You have to note that pure substances can be elements or compounds. There is only one component all throughout. On the other hand, a mixture is a combination of different elements and compounds. They can appear in different phases. For example, air is a mixture. It is composed of pure substances of oxygen, carbon dioxide, and nitrogen.
The answer is (3) 3. The outer shell of an atom is called valence shell. And the ground state is the lowest energy state of an atom. Aluminum has a electron distribution of 2, 8, 3. So the outer shell has 3 electrons.
Because the catalyst is not really part of the reaction. it is something that speed up a reaction by lowering the energy need for the reaction to take place. however, in the end the catalyst is brought back to its initial state. that's why it is long lasting
