Is tap water a compound, a homogenous mixture, or a heterogeneous mixture?

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

What are the similarities of physical and chemical change ?

What is the empirical formula of c6h18o3? ch3o c2h5o c2h6o c2h5o5