UW Chemistry Test 8

what does “like dissolves like” mean

polar dissolves polar; nonpolar dissolves nonpolar

miscible liquids

liquids that will mix in all proportions to form a homogenous solution

what factors speed up dissolving rates in gases

higher pressure, lower temperature (allows gas molecules to remain dissolved)

what factors speed up dissolving rates in solids/liquids

crushing/powdering (increases surface area), increasing temperature of solvent, stirring/agitating mixture

molarity (M)

moles of solute/L of solution

mass percent

mass of substance (100)/total solution mass

dissolving

when solid solute particles are pulled apart by the electrostatic forces of a solvent, forming an aqueous solution

when a compound breaks into individual particles

dissociating

when solid solute ions are pulled apart by the electrostatic forces of a solvent, forming a conductive aqueous solution

yields electrolytes, making solutions conductive

when an ionic compound breaks into individual ions

london dispersion

weakest, temporary, transient IMF present in nonpolar atoms and molecules

arise form temporary dipoles formed by the movement of electrons

dipole-dipole

occur between positive end of one polar molecule and negative end of another polar molecule

stronger than london dispersion forces

dipole-induced dipole

forces arise between polar and nonpolar molecules

hydrogen bonding

specialized dipole-dipole interaction occurring between a hydrogen atom bonded to a highly electronegative atom (N, O, F) and another electronegative N, O, or F atom in a nearby molecule

1 gram solute at 40 degrees F

supersaturated

0.69 gram solute at 40 degrees F

saturated

0.4 gram solute at 40 degrees F

unsaturated

strong forces at standard temperature (25 C)

solids, because particles are locked in place

higher boiling point (becomes gas at higher temp)

moderate forces at standard temperature (25 C)

liquids, because particles can move past each other but not escape

moderate boiling point (becomes gas at moderate temp)

weak forces at standard temperature (25 C)

gases, because particles have enough KE to break free and move independently

lower boiling point (becomes a gas at lower temp)

solvent

H2O in H2O + NaCl

solute

NaCl in H2O + NaCl

solution

H2O + NaCl

common types of IMFs strongest to weakest

ionic, hydrogen, dipole-dipole, london dispersion

insoluble salts

low ability as an electrolyte—no ions

slightly soluble salts

moderate ability as an electrolyte—few ions

soluble salts and strong acids/bases

good ability as an electrolyte—many ions