Classify each reaction as endothermic or exothermic.

h2 + br2 → 2hbr, δh = -73 kj
2nh3 → n2 + 3h2, δh = 92 kj
ch4 + 2o2 → co2 + 2h2o, δh = -890 kj
2hcl → h2 + cl2, δh = 184 kj

Summarize possible ways in which phases of matter could combine to form a solution.

21. consider the following chemical reaction: n2+ o2 2 no if 10.0 g of n2 reacts with excess oxygen then how many grams of no can be formed? a) 10.7 g b) 21.4 g c) 32.9 g d) 42.8 g page 4 of 8

Identify one disadvantage to each of the following models of electron configuration: -dot structures -arrow and line diagrams -written electron configurations type in your answer below. (answer) -dot structures do not show the distribution of electrons in orbitals and take up a lot of space. -arrow and line diagrams take up a lot of space and make it difficult to count electrons. -written configurations make it easy to lose count of electrons and do not show the distribution of electrons in orbitals.