Here it says calculate the total entropy change for reaction when the change in entropy of our surroundings equals 2.7 joules per Kelvin and the standard entropy change of our reaction equals negative -450 kilojoules per Kelvin, is this reaction spontaneous?

All right, so we need the total entropy. So delta S total here will equal delta S of my surroundings plus delta S standard of our reaction. Now here typically we'll have the change in our entropy being Joules per Kelvin. So I'll use this 2.7 joules per Kelvin.

Here I need to convert kilojoules to joules. Remember, 1K is 10 to the three, so that will come out to -450,000 joules per Kelvin. When we add them together we're going to get negative 449997.3 joules per Kelvin.

Because our change in total entropy is a negative value, that would mean that this is a non spontaneous reaction. OK, so here we'd say it's non spontaneous for this particular example.