The enthalpies of formation of the compounds in the combustion of methane, , are ch4 (g): hf = –74.6 kj/mol; co2 (g): hf = –393.5 kj/mol; and h2 o(g): hf = –241.82 kj/mol. how much heat is released by the combustion of 2 mol of methane? use . 80.3 kj 802.5 kj 1,605.1 kj 6,420.3 kj

ΔH°c = - 1605.1 KJ

Explanation:

∴ ΔHf CH4(g) = - 74.6 KJ/mol

∴ ΔHf CO2(g) = - 393.5bKJ/mol

∴ ΔHfH2O(g) = - 241.82 KJ/mol

standard enthalpy of combustion (ΔH°c):

⇒ ΔH°c = (2)(ΔHf H2O) + ΔHfCO2 - ΔHfCH4

⇒ ΔH°c = (2)(- 241.82) + ( - 393.5 ) - ( - 74.6 )

⇒ ΔH°c = - 802.54 KJ/mol

⇒ ΔH°c = ( - 802.54 KJ/mol )(  2 mol CH4 )

⇒ ΔH°c = - 1605.08 KJ

gravity causes stares to cluster i think so

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.