Final answer:
Ideal solutions occur when the intermolecular forces in the solution are equal to those in the separate components, with gases like helium and argon as examples. Non-ideal solutions display energy changes due to different intermolecular forces upon mixing, with examples including deviations from Raoult's law.
Step-by-step explanation:
When discussing the terms ideal and non-ideal solutions, it's essential to focus on the intermolecular forces, which are the attractions between the molecules within a solution. In an ideal solution, these forces between solute and solvent are equal to the intermolecular forces found in the pure components, resulting in no net energy change upon mixing. For instance, when ideal gases like helium and argon are combined, they form an ideal solution, displaying no significant intermolecular attraction. Both gases behave ideally under conditions of high temperature and low pressure.
In contrast, non-ideal solutions exhibit changes in energy due to the differences in intermolecular forces upon mixing. These solutions might have stronger or weaker attractions compared to the separate solute and solvent, leading to positive or negative deviations from Raoult's law, which is used to predict the vapor pressures of ideal solutions. The van der Waals equation is applied to non-ideal gases to account for the non-ideal behaviors, particularly at lower temperatures and higher pressures, where gases display significant interactions and finite size.
Understanding whether a liquid is polar or nonpolar can help predict the type of intermolecular interactions and, consequently, whether a solution will be ideal or non-ideal. Intermolecular forces are crucial in explaining the physical properties of matter and the deviations from ideal behavior in liquids and gases.