In AP Chemistry, a solvent is the substance present in the largest amount in a solution that dissolves the solute, with dissolving driven by intermolecular interactions ('like dissolves like'). Water is the most common solvent on the exam, making aqueous (aq) solutions.
A solvent is the substance that does the dissolving in a solution. The solute is what gets dissolved, and the solvent is the medium it disappears into. In most AP Chem problems the solvent is water, which is why you see (aq) all over net ionic equations. But solvents can be any phase. Solutions themselves can be solids, liquids, or gases, and what makes them solutions (homogeneous mixtures) is that the properties are the same everywhere in the sample.
The deeper AP-level idea is why a solvent dissolves something. It comes down to intermolecular forces. Per the CED (3.10.A.1), substances with similar intermolecular interactions tend to be miscible or soluble in one another. That's the famous rule of thumb 'like dissolves like.' Polar water dissolves ionic salts and polar molecules because ion-dipole and dipole-dipole attractions can replace the attractions inside the solute. Nonpolar solvents like hexane dissolve nonpolar solutes through dispersion forces. If you can match the solvent's IMFs to the solute's IMFs, you can predict solubility.
Solvent shows up in three different units, which makes it one of the most cross-cutting terms in the course. In Unit 1, mixtures versus pure substances (1.4.A) sets up what a solution even is. Unit 3 is the heart of it. You calculate molarity using liters of solution (3.7.A, M = n/L), draw particulate diagrams showing solvent molecules surrounding solute particles (3.8.A), explain chromatography where the solvent is literally the mobile phase (3.9.A), and predict solubility from intermolecular interactions in aqueous and nonaqueous solvents (3.10.A). Then Unit 7 brings it back. When you compute solubility from Ksp (7.11.A), you're modeling how much salt a solvent can hold at equilibrium in a saturated solution. If a question involves dissolving anything, the solvent's identity and its IMFs are usually doing the explanatory work.
Keep studying AP Chemistry Unit 3
Solute (Units 1, 3, 7)
Solute and solvent are two halves of every solution. The solvent dissolves; the solute gets dissolved. On particulate diagrams, the solvent molecules should outnumber and surround the solute particles, and for ionic solutes in water, the partial charges of water must point the right way toward each ion.
Intermolecular Interactions (Unit 3)
Solubility is an IMF story. A solvent dissolves a solute when the new solvent-solute attractions are comparable to the attractions each substance had on its own. That's why polar solvents grab polar and ionic solutes while nonpolar solvents grab nonpolar ones. 'Like dissolves like' is really 'matching IMFs dissolve each other.'
Chromatography (Unit 3)
In paper or thin-layer chromatography, the solvent is the mobile phase. Components that interact more strongly with the solvent travel farther; components that stick to the stationary phase lag behind. Choosing a more or less polar solvent changes which components move, which is exactly what the 2017 dye chromatography FRQ tested.
Solubility Equilibria and Ksp (Unit 7)
Dissolution in a solvent can be modeled as an equilibrium system. A saturated solution is one where the solvent has dissolved all it can at equilibrium, and Ksp quantifies that limit. Unit 7 turns the qualitative Unit 3 picture into a calculation.
Solvent rarely gets tested as a standalone definition. Instead it's the setup for what you actually have to do. MCQs ask you to pick which solvent dissolves a given compound (justify with IMFs), interpret particulate diagrams of solute surrounded by solvent, or explain chromatogram results based on solvent polarity. FRQs use it in lab contexts. The 2024 short FRQ had you prepare 100.0 mL of 0.340 M NaCl(aq) as a chromatography solvent, which means converting molarity to grams of solute and describing solution prep with a volumetric flask. The 2017 short FRQ asked you to reason about dye separation based on attractions between dyes, solvent, and paper. Two warnings from the CED itself. Colligative properties (boiling point elevation, etc.) are not assessed, and molality, percent by mass, and percent by volume calculations are not assessed. Molarity is the concentration unit the exam cares about.
The solvent does the dissolving; the solute is what gets dissolved. The solvent is the component present in the larger amount. In saltwater, water is the solvent and NaCl is the solute. The mix-up matters in molarity problems, where the denominator is liters of total solution, not liters of solvent, and in particulate diagrams, where mislabeling which particles are which costs points.
The solvent is the substance present in the largest amount in a solution, and it dissolves the solute; in aqueous (aq) solutions, water is the solvent.
Solubility follows 'like dissolves like' because substances with similar intermolecular interactions tend to be miscible or soluble in one another (CED 3.10.A.1).
Molarity is moles of solute per liter of solution (M = n/L), and it's the only concentration calculation the AP exam assesses, since molality and percent composition are excluded.
In chromatography, the solvent is the mobile phase, and components separate based on how strongly they're attracted to the solvent versus the stationary phase.
Dissolving a salt in a solvent can be modeled as an equilibrium system, and Ksp tells you how much solute a saturated solution holds (Unit 7).
On particulate diagrams, draw solvent molecules surrounding solute particles with correct orientation, like water's partial negative oxygen pointing toward cations.
A solvent is the substance that dissolves a solute to form a solution, and it's usually the component present in the largest amount. Water is the most common solvent on the AP exam, which is why dissolved species get the (aq) label.
The solvent does the dissolving and is present in the larger amount; the solute is what gets dissolved. In 5.85 g of NaCl dissolved in 100.0 g of water, water is the solvent and NaCl is the solute.
No. Water is polar, so it dissolves ionic compounds and polar molecules well, but it's bad at dissolving nonpolar substances like oils. The CED rule is that substances with similar intermolecular interactions dissolve in each other, so nonpolar solutes need nonpolar solvents.
Yes, indirectly. Molarity is moles of solute divided by liters of total solution, which includes the solvent. It is not moles per liter of solvent alone, and mixing those up is a classic point-loser.
No. The CED explicitly states that colligative properties and calculations of molality, percent by mass, and percent by volume will not be assessed. Focus on molarity (M = n/L) and dilution instead.