What is the formula for percent by mass in chem

How many moles of oxygen react with 12 moles of aluminum

Which statement is true about the model of the electromagnetic spectrum a: it change the frequencies of light. b: it compare wavelengths of light. c: the color of light waves can be changed using the model. d: the intensities of light waves can be decreased using the model.

Name 3 types of energy you see being used as you look around a classroom