Why do intermolecular forces exist between water molecules?

One or more substances changing into one or more substances is an example of a

What is avogadro’s number, and why is it useful

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