One mole of an atom of a substance is equal to

One mole of a substance is equal to 6.022 × 10²³ units of that substance (atoms, molecules, or ions)

Explanation:

This number is Avogadro's number. The concept of the mole can be used to convert between mass and number of particles. its used to compare very large numbers.

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.