make or become hot or warm is heating.
cooling is to become colder or cool down from a higher temp.
The number of moles of sodium dichromate from the number of moles of oxygen atoms can be determined through stoichiometry. Using the molecular formula of the compound, Na2Cr2O7, 1 mole of the compound contains 7 moles of oxygen. Hence, 14 moles O2*(1 mole Na2Cr2O7/ 7 mole O2) is equal to 2 moles <span>Na2Cr2O7.</span>
Because the proton has a mass of 1 and a neutron has a mass of 1, we know that there is exactly one proton in the nucleus (because of the atomic number) which therefore tells us there are no neutrons as adding one would make the mass more than one.
