Question

Which of the following combinations will result in a reaction that is spontaneous at all temperatures?

positive enthalpy change and positive entropy change

positive enthalpy change and negative entropy change

negative enthalpy change and positive entropy change

negative enthalpy change and negative entropy change

Answer 1

You're being asked to remember and use the standard relationship between change in Gibbs free energy dG, change in enthalpy dH, and change in entropy dS:
\[\Delta G = \Delta H - T \Delta S\]
where T is the *absolute* temperature, usually measured in kelvins. The other key fact you'll need is that only reactions with dG > 0 are spontaneous.

Answer 2

oh. ok. thankyou.