Hey! I need help with this chemistry/math problem. Give me the Answer please

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

Which of the following would have less momentum than a 52 kg cheetah running at 10 m/s?

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.