What are some economic impacts of calcium?

Which of the following is a testable hypothesis? a. if i brush my teeth, i will get fewer cavities than if i don't brush my teeth. b. green toothpaste tastes better than blue toothpaste or red toothpaste. c. smart, careful, healthy people always brush their teeth. d. it's wrong to not brush your teeth before you have an important conversation with someone.

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

Under normal conditions, describe how increasing the temperatures effects the solubility of a typical salt