Recent content by tester.dla.mmc

Thanks for so fast response. ΔfH (Na+(aq)) value in my book was given without sign (probably author just forgot about it) and I assumed that it must be positive since losing electron is usually positive (didn't take into consideration that is't (aq) ion) but now everything makes much more...

NaOH dissociation is exothermic so ΔH<0 But when I have a reaction NaOH(s) => Na+(aq) + OH-(aq) and count ΔrH using standard entalphy change of formation: ΔfH (NaOH) = -425 kj/mol ΔfH (OH-(aq)) = -230 kj/mol ΔfH (Na+(aq)) = +242 kj/mol Data from Atkins phisical chemistry basics...