The correct question is as follows: 0.500 moles of potassium oxide is dissolved in enough water to make 2.00 L of solution. Calculate the molarity of this solution (plz help!)
Answer: The molarity of this solution is 0.25 M.
Explanation:
Molarity is the number of moles of a substance divided by volume in liter.
As it is given that there are 0.5 moles of potassium oxide in 2.00 L of water so, the molarity of this solution is calculated as follows.

Thus, we can conclude that molarity of this solution is 0.25 M.
20 grams is probably the mass
Molarity is simply the ratio of the number of moles of a
substance over the total volume of the solution. Assuming that the addition of
0.850 moles does not change the overall volume of 1.70 L, therefore molarity is
simply:
Molarity = 0.850 moles / 1.70 L = 0.5 moles / L = 0.5 M
I would say the energy has to be decreased by 87 kj because the bonding is held together by 87 kj so removing that should prevent the bonding from taking place or reverse it I believe. In other words, a certain amount of energy is required to hold the bond together and in the absence of that energy, the bonding will not take place.