If you need to multiply the following reaction by 2 to be an intermediate reaction in a Hess's law problem, what would be the final value for the
enthalpy of reaction you use for this intermediate reaction? C2H4 +3 02-2
CO2 + 2 H20, AH = -1410 kJ
A. 2820 kJ
B. -1410 kJ
C. -2820 kJ
D. 1410 kJ
PLEASE HELP ITS DUE TONIGHT

c) should be the answer.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.