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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Ilikebugs on April 24, 2019, 06:45:02 PM

Title: Correct equations using energy
Post by: Ilikebugs on April 24, 2019, 06:45:02 PM

Which of the following equations is not correct?
A| H2 (g) -> 2H (g) + energy
B| Na(g) + e - -> Na-(g) + energy
C| Mg(g) + energy -> Mg 2+ (g) + 2e -
D| Cu(s) + energy -> Cu(l)
E| Na + (g) + Cl - (g) -> NaCl(s) + energy

I don't see any problem with them where energy is on the left for decomposition and on the right for synthesis, is there no energy needed to change the state of copper perhaps?

Title: Re: Correct equations using energy
Post by: Mitch on April 24, 2019, 11:32:03 PM

Does A look right to you?

Title: Re: Correct equations using energy
Post by: Ilikebugs on April 25, 2019, 09:30:34 PM

Oh, is A wrong because it decomposes but it outputs energy?

Title: Re: Correct equations using energy
Post by: Enthalpy on April 26, 2019, 05:36:34 AM

The atomization of H₂ absorbs energy.

I've seen "decomposition" said from other reactions, like acetylene producing soot and gases, which does release energy, boom.