Question

實(shí)驗(yàn)測得碳單質(zhì)、氫氣、甲烷的燃燒熱（△H）分別為-393.5 kJ/mol、-285.8 kJ/mol、-890.3 kJ/mol。則
CH₄(g) == C(s) + 2H₂(g)的反應(yīng)焓變（△H）為

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A．-74.8 kJ/mol
B．+74.8 kJ/mol
C．-211kJ/mol
D．+211kJ/mol

Answer 1

B