You are supposed to get low toward the floor if you are ever caught in a building or house fire. The hotter air and smoke will rise and the cooler air will sink. What type of heat transfer does this represent?

a corroding iron, if that's one of your choices

it should have an internal chamber and two thermometers sticking out of the top. the internal chamber will also be closed off from the outside.

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.