can anyone help me with this?

Question

1. do all solutes dissolve to the same extent in the same solvent? how do you know

Answer 1

No, they do not. Some are very soluble, others hardly at all. Consider the solubility of sodium chloride and silver chloride in water. One can know from experience.

Answer 2

During solvation, especially when the solvent is polar, a structure forms around it, which allows the solute-solvent interaction to remain stable.

When no more of a solute can be dissolved into a solvent, the solution is said to be saturated. However, the point at which a solution can become saturated can change significantly with different environmental factors, such as temperature, pressure, and contamination. For some solute-solvent combinations a supersaturated solution can be prepared by raising the solubility (for example by increasing the temperature) to dissolve more solute, and then lowering it (for example by cooling).

Usually, the greater the temperature of the solvent, the more of a given solid solute it can dissolve. However, most gases and some compounds exhibit solubility that deacrease with increased temperature. Such behavior is a result of an exothermic enthalpy of solution. Some surfactants exhibit this behaviour. The solubility of liquids in liquids is generally less temperature-sensitive than that of solids or gases

Answer 3

No, not all solutes are soluble to the same extent in a single solvent.
As you probably know, like dissolves in like, simply put. Meaning that polar compounds dissolve in polar compounds.
However, certain compounds can range from being quite reasonably polar like methanol (CH3OH), because it has a readily exposed oxygen which acts as an electron donor and hydrogens, particularly the one bonded to the oxygen as an electron acceptor for other molecules so both can engage in hydrogen bonding which is an important property in solvation of polar molecules.
But for molecules with a larger number carbons, and various branches, but only one OH group, excluding amines (Nitrogen groups), these molecules become less polar with size overall, and therefore less soluble in water.

All the other answers were good, but it's good to get different interpretations and explanations in order to understand.

Answer 4

Obviously not true. Different compounds have different characteristics, and would have no reason to dissolve to the same extent.

This is best seen in this chart:
http://www.thesciencedesk.com/SolubilityGraph.html