Define trace gas in simple ​

Determine the number o moles of ions/atoms/particle in the following: 2.50 miles of k2s (let me know how to do)

Afusion reaction takes place between carbon and another element. neutrons are released, and a different element is formed. the different element is a) lighter than helium. b)heavier than helium. c)the same weight as helium. d)dependent on the element that reacted with carbon.

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.