What describes a change that occurs when one substance reacts to another substance?

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 .

2h2s + 3o2 2so2 + 2h2o which option gives the correct mole ratios? h2s: so2 = 2: 2 and o2: h2o = 3: 2 h2s: so2 = 2: 3 and o2: h2o = 3: 2 h2s: so2 = 4: 4 and o2: h2o = 5: 4 h2s: so2 = 4: 6 and o2: h2o = 4: 4

Start an single atom tab. observe the decay of polonium-211. after each decay, press the reset nucleus button to watch the process again. write a description of alpha decay for po-211