A substance that produces ions when it dissolves, so that its solution conducts electricity, is called an electrolyte.
Missing Word
electrolyte
An electrolyte yields ions in solution, either by dissociating or by reacting with the solvent. The mobile ions are what allow the solution to conduct electricity.
Category: Electrolytes
Question 2
The physical separation of an ionic solid's cations and anions as they spread out into water is called dissociation.
Missing Word
dissociation
Dissociation is the process by which an ionic compound's ions separate and disperse in solution. It differs from ionization, in which a molecular compound reacts to form ions that were not present before.
Category: Electrolytes
Question 3
Salts of fatty acids, made by treating animal fats or oils with a strong base, are called soaps.
Missing Word
soaps
Soaps are the sodium or potassium salts of fatty acids. Each soap ion has a long nonpolar hydrocarbon tail and an ionic carboxylate end, which is what lets it suspend oily dirt in water.
Category: Colloids
Question 4
Instant cold packs work because ammonium nitrate dissolving in water is an endothermic process.
Missing Word
endothermic
An endothermic process absorbs heat from the surroundings, so the pack becomes cold. Ammonium nitrate still dissolves spontaneously because the dispersal of matter increases.
Category: Dissolution Process
Question 5
A solid solution of one metal dissolved in another, such as brass, is called an alloy.
Missing Word
alloy
An alloy is a solid solution of metals; brass is zinc dissolved in copper. Alloys show that solutions are not limited to liquids.
Category: Dissolution Process
Question 6
The maximum concentration of a solute that can dissolve in a given solvent at equilibrium under specified conditions is the solute's solubility.
Missing Word
solubility
Solubility is the equilibrium limit for how much solute a solvent can hold under given conditions such as temperature and pressure. A solution at this concentration is saturated.
Category: Solubility
Question 7
When the solvent is water, the solvation of dissolved ions by surrounding water molecules is specifically called hydration.
Missing Word
hydration
Hydration is solvation in which the solvent is water: water molecules cluster around each ion, attracted by ion-dipole forces. This weakens the attractions holding the ions together and stabilizes them in solution.
Category: Electrolytes
Question 8
A solution that contains more dissolved solute than it can hold at equilibrium, an unstable state that a seed crystal can end, is called supersaturated.
Missing Word
supersaturated
A supersaturated solution holds solute beyond its solubility and is not at equilibrium. Adding a seed crystal or agitating it causes the excess solute to crystallize, as in sodium acetate hand warmers.
Category: Solubility
Question 9
The concentration unit defined as moles of solute per kilogram of solvent is molality.
Missing Word
molality
Molality is moles of solute divided by kilograms of solvent, with units of mol/kg (m). Because it depends on masses, it does not change with temperature.
Category: Concentration Units
Question 10
Properties such as boiling point elevation that depend on the number of dissolved solute particles rather than their identity are called colligative properties.
Missing Word
colligative
Colligative properties depend only on the concentration of solute particles. The four are vapor pressure lowering, boiling point elevation, freezing point depression and osmotic pressure.
Category: Colligative Properties
Question 11
Dividing the moles of dissolved substance by the volume of the whole solution in liters gives the concentration unit called molarity.
Missing Word
molarity
Molarity (M) is moles of solute divided by liters of solution. Because solution volume changes with temperature, molarity also changes slightly with temperature, unlike molality.
Category: Concentration Units
Question 12
The net movement of solvent molecules through a semipermeable membrane from a dilute solution into a more concentrated one is called osmosis.
Missing Word
osmosis
Osmosis is the net flow of solvent across a membrane that blocks solute particles. The pressure needed to stop this flow is the osmotic pressure.
Category: Colligative Properties
Question 13
Separating the components of a liquid mixture by selective vaporization, based on their different vapor pressures, is called distillation.
Missing Word
distillation
Distillation boils off the more volatile component and condenses it separately. Crude oil is separated this way in a fractionating column.
Category: Colligative Properties
Question 14
A colloid in which tiny droplets of one liquid are dispersed throughout another liquid, as in milk, is called an emulsion.
Missing Word
emulsion
An emulsion is a liquid-in-liquid colloid. Because the droplets tend to merge, emulsions are usually stabilized by an emulsifying agent, such as casein in milk or egg yolk in mayonnaise.
Category: Colloids
Question 15
A colloid in which gas bubbles are dispersed in a liquid, as in whipped cream, is called a foam.
Missing Word
foam
A foam is a gas-in-liquid colloid; whipped cream and beaten egg whites are examples. Gas dispersed in a solid, as in pumice, is a related but different colloid type.
Category: Colloids