How many valance electrons does oxygen have

Predict whether the changes in enthalpy, entropy, and free energy will be positive or negative for the boiling of water, and explain your predictions. how does temperature affect the spontaneity of this process?

Which process results in the release of energy stored in the products of photosynthesis? a. polymer synthesis b. depolymerization c. digestion d. cellular respiration

Ablock of aluminum is dropped into a graduated cylinder with an initial volume of water at 75ml and the volumes rises to 90ml. if the block has a mass of 40.5 g what is its density ?