Work done by a system is positive or negative?

Gravitational potential energy is related to

Use the drop-down menus to label each of the following changes p for physical change and c for chemical change. the substance changes to a new substance. the original substance can be recovered. the color changes. gas is produced and given off. the substance changes size, shape, or volume.

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.