01. Determine the enthalpy of reaction for: 2 N2(g) + 5 O2(g) à 2 N2O5(g) ΔH°rxn = ? Given the following equations:

2H2(g) + O2(g) à 2 H2O(l) ΔH°rxn = –571.6 kJ
N2O5(g) + H2O(l) à 2 HNO3(l) ΔH°rxn = –73.7 Kj
N2(g) + 3 O2(g) + H2(g) à 2 HNO3(l) ΔH°rxn = –348.2 kJ

Water ionizes by the equation h2o(l)⇌h+(aq)+oh−(aq) the extent of the reaction is small in pure water and dilute aqueous solutions. this reaction creates the following relationship between [h+] and [oh−]: kw=[h+][oh−] keep in mind that, like all equilibrium constants, the value of kw changes with temperature.

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.

Given the following at 25c calculate delta hf for hcn (g) at 25c. 2nh3 (g) +3o2 (g) + 2ch4 (g) > 2hcn (g) + 6h2o (g) delta h rxn= -870.8 kj. delta hf=-80.3 kj/mol for nh3 (g), -74.6 kj/mol for ch4, and -241.8 kj/mol for h2o (g)