Why do covalent compounds have significantly lower melting/boiling points than ionic compounds?

In the following redox reaction which is the oxidizing agent and which is the reducing agent? alcl3 + na nacl + al

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

Which of the following words describe the reality that the universe looks the same from various perspective