Question

smoker’s toothpaste actually has corundum in it!
corundum has a hardness of 9 on moh’s hardness scale.
how hard is corundum relative to the apatite that makes up your teeth?
fun fact. corundum comes in 3 colors. what you may know as a sapphire is actually blue corundum. what you may know as a ruby is actually red corundum!
(the color varies depending on what sorts of impurity gets incorporated into the crystal structure of the mineral)
corundum is harder than the apatite that makes up your teeth
corundum is softer than the apatite that makes up your teeth
question 42
2.22 pts
which abrasive minerals are present in your tube/box of toothpaste?

Explanation:

First Part (Multiple - Choice)

Apatite has a hardness of 5 on Moh's hardness scale, and corundum has a hardness of 9. Since 9 > 5, corundum is harder than apatite.

Common abrasive minerals in toothpaste include corundum (as mentioned for smoker's toothpaste), also silica (silicon dioxide) is a very common abrasive mineral in many toothpastes. Other possible ones could be calcium carbonate, etc. But from the given context about corundum in smoker's toothpaste, corundum is one, and generally, silica is a major abrasive mineral in toothpaste.

Answer:

Corundum is harder than the apatite that makes up your teeth

Second Part (Short - Answer)