How does crystals apply to a real world problem

What is important to study for nios grade 12 chemistry? i have only one month left.

What is the number of moles in 15.0 g ash3?

Transportation is the largest single source of air pollution in the united states. air pollution can harm the environment and human health. which technology could offer a solution to this problem? mufflers that reduce noise motors that run on electricity tires that improve gas mileage