If a calcium supplement claims to have 200 mg of calcium per pill - how much mass if each pill if the supplement is a calcium sulfate compound?

Ineed with my science work! it’s due tomorrow!

What reaction is taking place? 02 + c3h8 = h20 + co2

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line