Describe three physical changes that occur in nature.

Nitric oxide (no) can be formed from nitrogen, hydrogen and oxygen in two steps. in the first step, nitrogen and hydrogen react to form ammonia: n2(g) + 2 h_2(g) rightarrow 2 nh_3 (g) delta h = -92. kj in the second step, ammonia and oxygen react to form nitric oxide and water: 4 nh_3(g) + 5 o_2(g) rightarrow 4no(g) + 6 h_2o(g) delta h = -905. kj calculate the net change in enthalpy for the formation of one mole of nitric oxide from nitrogen, hydrogen and oxygen from these reactions. round your answer to the nearest .

9. write the chemical equation for the following word equations. include symbols for physical states in the equation. a. solid zinc sulfide + oxygen gas -> solid zinc oxide + sulfur dioxide gas b. aqueous hydrochloric acid + aqueous barium hydroxide -> aqueous barium chloride + water

Which part of a feedback mechanism is able to monitor the conditions outside of cells and usually uses nerve cells to relay this information to an intergrating center