Moles and Percent Comp by Mass
Moles are central to chemistry. They involve a fair amount of math, and a lot of thinking. This is not a topic to blow off, you will need to use moles throughout the rest of the year. It is truly AMAZING how connected all the parts of chemistry become once you see this in action.
And, there’s a really cool shark.
As for Percent Composition by Mass, this part is sort of like figuring out what the mass of the bananas are in a whole fruit salad by a percentage. There are never enough bananas, so your answer can be not enough bananas, and that’s usually good for at least one point!
Get psyched, I love this part of chem.
Peace, Love, and Chemistry.