How many molecules are in 2.50 moles of h2o? ?

Moles of H2O = 2.5moles. Number of molecules of H2O = 2.5 x 6.02x 10^23 = 1.505x10^24. Hope it helps.

Your answer is a just took the test

Answerδh > 0explanationc₆h₆  (s)  → c₆h₆ (l)if you are changing it from a solid to a liquid, you are pretty much melting the solid. this requires heat energy. therefore, the reaction is endothermic (takes in energy); the system enthalpy increases as the reaction proceeds: δh > 0.