Many portable gas heaters and grills use propane, C3H8(g). Using enthalpies of formation, calculate the quantity of heat produced when 15.0 g of propane is completely combusted in air under standard conditions. Assume that liquid water is forming.

Chemistry worksheet - i am not sure what they are asking for exactly?

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.

The same side of the moon always faces earth because the