For a particular isomer of C8H18, the combustion reaction produces 5099.5 kJ of heat per mole of C8H18(g) consumed, under standard conditions. C8H18(g)+252O2(g)⟶8CO2(g)+9H2O(g)Δ∘ rxn=−5099.5 kJ/mol

What is the standard enthalpy of formation of this isomer of C8H18(g)?
Δ∘f= kJ/mol

Which set of characteristics best describes igneous rock? a) largest type of rock, made of organic matter, hardest type of rock b) least abundant type of rock, made of other rocks, made mostly of minerals c) found on all continents, contains wavy bands of stripes, contains fossils d) most abundant type in earth's crust, made of magma/lava, contains no fossils