Which would most likely be done while designing a solution? researching the current uses of a fuel type sketching a diagram of a new medical device reporting the results of using a prototype redesigning a model airplane that did not fly well

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.