<span>Mg + O2 > MgO. In reactant side, 2 O atoms and 1 Mg are present. In product side, 1 Mg and O atoms are present. Put 2 in product side to balance O atoms and 2 at Mg in reactant side to balance Mg atoms. Therefore the balanced equation becomes, 2Mg + O2 ----> 2MgO. Hope it helps.</span>
Answer:
I think beaker three will take longer to boil since there is more water present,compared to the other beakers
Mass equals density times volume
Because D=m/v
Multiply by v
Dv=m