11) Nitrogen oxides undergo many interesting reactions in the environment and in industry. Given the following information, calculate H for the overall equation: 2 NO2(g) + 1/2 O2(g) N2O5(s).
N2O5(s) 2 NO(g) + 3/2 O2(g), deltaH = 223.7 kJ

NO2(g) NO(g) + 1/2 O2(g), delataH = 57.1 kJ

delataH = kJ

12Write all coefficients, even if they are fractions or 1.)
(a) (Apply fractions as needed.)
(s) + (g) 5 NaCl(s)
(b) (Use the lowest possible coefficients.)
(s) + (g) CaCl2(s)
(c) (Apply fractions as needed.)
(g) O3(g)
(d) (Apply fractions as needed.)
Mg(s) + (s) + (g) Mg3(PO4)2(s)

When the following equation is balanced using the smallest possible integers, what is the coefficent of oxygen gas? c7h16o(g) + o2(g) → co2(g) + h2o(g) -1 -5 -8 -16 -21

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)