1. What does it mean for a substance to be soluble?

Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. It is measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium. ... Certain substances are soluble in all proportions with a given solvent, such as ethanol in water.

Explanation:

pure water does not conduct electricity very well. however, when certain substances are dissolved in water, the solution does conduct electricity. you can make a simple device that shows how well a solution conducts electricity. this device uses a flashlight bulb to indicate how well the solution conducts electricity. the better the solution conducts electricity, the brighter the bulb will glow.

explanation:

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)