Which of the following should be classified as a mixture? water air iron helium

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 .

Monkeys and bats have similar bone structure in their forelimbs. however, monkeys have longer forelimbs to use for climbing and swinging in trees. bats have shorter forelimbs to use for flight. which term best describes how monkey and bat forelimbs are related to each other? a. homologous b. embryonic c. analogous d. vestigial

Why does his teacher ask him to balance the equation by including the correct coefficient