many portable gas heaters and grills use propane, c3h8(g). using enthalpies of formation, calculate the quantity of heat produced when 13.0 g of propane is completely combusted in air under standard conditions. assume that liquid water is forming.

Which of the following ideas did greek philosopher democritus contribute to the atomic theory? a. each object is made up of one atom, which varies in size from very small to very large. b. matter is composed of only one kind of particle, which can be easily destroyed. c. every element has a specific type of atom, which remains the same size in all forms of matter. d. all matter is composed of small particles, which combine to make larger objects.