9.Out of the following which is a poly atomic molecule. (H2, CI 2.03.)​

Is this a single replacement reaction or there is no

An atom with 7 protons, 6 neutrons, and 7 electrons has an atomic mass of amu. (enter a whole number.) numerical answers expected! answer for blank 1:

The fact that the total amount of energy in a system remains constant is a(n)