How many moles are 2.54×10^29 molecules of H20?​

421,787 moles.

Explanation:

No. of Molecules of H20=2.54×10²⁹

1 mole=6.022×10²³=Avagadro No.

No. of moles=Given no. of moles/Avagadro No.

=(2.54×10²⁹)/(6.022×10²³)=421,786.782=421,787(approx)

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.