In an isotope, which subatomic particle varies in number ?

Which compound contain an iron with a 3+ charge

Suppose you mix one mole of sulfuric acid (h2so4) with 1 mole of sodium hydroxide(naoh). why does the ph of the solution remain below 7? ( explain so i can get better understanding! )

8) warming your hands by a fire is an example if which heat transfer? a. conduction b. convection c. radiation d. none of these