What is the amplitude of the above wave? What is the frequency of the above wave?
What is the wavelength of the above wave?

the answer is d. 74.02

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.

yes the answer is total mass in unchanged   : )