What is the total number of neutrons in an atom with a mass number of 3 and an atomic number of 1

2 neutrons

Explanation:

3-1=2

protons and neutrons equal the atomic mass...

the atomic number is the number of protons so take the mass- the protons and you get the neutrons

a. as the temperature increases, the kinetic energy of the gas molecules increases & the molecules move faster & further away from each other.

b. if you decrease the temperature of a fixed amount of gas at constant pressure, the combined gas law reduces to charles's law. in this case, volume will also decrease.

yes, because even though a theory has a  lot of evidence to support it, it is not always true