Calculate the standard enthalpy change for the reaction 2A+B⇌2C+2D

where the heats of formation are given in the following table:
Substance ΔH∘f
(kJ/mol)
A -235
B -407
C 209
D -519
Express your answer in kilojoules.

Idon't really understand this can you me and show your work.☺☺[ chemistry b] subject [ electron transfer in lonic bonds]grade( 12)

What is the atomic mass of an atom that has 6 protons, 6 neutrons, and 6 electrons? a) 6 b) 8 c) + 1 d) 12 e) 18

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