A typical cold pack involves mixing a solid salt, such as ammonium nitrate, with water. In other words, the cold pack you might buy at a pharmacy to put on a sprained ankle is just a dissolution chemical reaction. This reaction must be:: a. Exothermic and spontaneous
b. Endothermic and spontaneous
с. Endothermic requiring work
d. Exothermic requiring work
e. Not enough information

A0.10 m aqueous solution of sodium sulfate is a better conductor of electricity than a 0.10 m aqueous solution of sodium chloride. which of the following best explains this observation? (a) sodium sulfate is more soluble in water than sodium chloride. (b) sodium sulfate has a higher molar mass than sodium chloride. (c) to prepare a given volume of 0.10 m solution, the mass of sodium sulfate needed is more than twice the mass of sodium chloride needed. (d) more moles of ions are present in a given volume of 0.10 m sodium sulfate than in the same volume of 0.10 m sodium chloride. (e) the degree of dissociation of sodium sulfate in solution is significantly greater than that of sodium chloride.