Astronomers believe there are billions of galaxies in the universe. Which of the following is NOT found in all galaxies? A. Asteroids
b. Meteors
c. Comets
d. Planets

3. how much energy in joules is required to evaporate .0005 kg of liquid ammonia to vapor at the same temperature? 4. how much energy ( in megajoules ) is given up by .75 kg of water at 0c when it freezes to form ice at 0c? 5. explain how heat works between and at critical temperatures?

What is the percent by mass of magnesium sulfate in mgso4.7h2o

On the periodic table, elements are arranged by which of the following. a. mass numbers. b. increasing atomic number. c. alphabetical order. or d. density