We can use hess's law to calculate enthalpy changes that cannot be measured. one such reaction is the conversion of methane to ethylene: 2ch4(g)⟶c2h4(g) 2h2(g) part a calculate the δh∘ for this reaction using the following thermochemical data: ch4(g) 2o2(g)⟶co2(g) 2h2o(l) δh∘

Select the correct value for the indicated bond angle in each of the compounds. o−o−oo−o−o angle of o3 90° 109.5° < 109.5° 120° < 120° 180° f−b−ff−b−f angle of bf3 180° < 109.5° < 120° 120° 109.5° 90° f−o−ff−o−f angle of of2 < 120° 120° 90° 109.5° 180° < 109.5° cl−be−clcl−be−cl angle of becl2 90° 109.5° 180° 120° < 109.5° < 120° f−p−ff−p−f angle of pf3 90° 109.5° < 109.5° 180° 120° < 120° h−c−hh−c−h angle of ch4 90° < 109.5° 180° 120° < 120° 109.5°