AP CHEM: Unit 3 Solutions (Sec 1)

quizlet ai and chem notes

What is a homogeneous mixture in which one substance is dissolved in another?

Solution

What is the substance that is dissolved in a solution?

Solute

What is the substance doing the dissolving in a solution?

Solvent

What term describes a substance that does NOT dissolve?

Insoluble

What term describes a substance that does dissolve?

Soluble

What type of solution contains the maximum quantity of solute that can dissolve at a given temperature?

Saturated solution

What type of solution contains less than the maximum amount of solute that can be dissolved?

Unsaturated solution

What type of solution contains more solute than is possible to be dissolved, making it unstable?

Supersaturated solution

What is the process called when ionic solids dissolve in water and separate into their ions?

Dissociation

What is the term for substances that do not form ions or conduct electric current?

Nonelectrolytes

What is the term for the process that stabilizes ions in a solution?

Solvation

What interactions are involved in a solution?

Solute-solute, solvent-solvent, and solute-solvent interactions

What must happen for a solution to form regarding attractive forces?

Attractive forces between solute and solvent must be greater than those between solute-solute or solvent-solvent.

What happens to energy during the separation of solute into smaller components?

It requires energy input (endothermic process).

What is the ΔH for the formation of solute-solvent interactions?

It is exothermic (ΔH < 0).

What does a positive ΔHsoln indicate about a solution's formation?

The solution formation is endothermic.

What does the Solubility Product Constant (Ksp) indicate?

How soluble a solid is in water.

What is the Ksp expression for BaSO4(s) ⇌ Ba2+(aq) + SO42-(aq)?

Ksp = [Ba2+][SO42-]

What happens to Ksp as the amount of solid that dissolves increases?

Ksp increases.

What is the difference between solubility and Ksp?

Solubility is measured in g/L or moles/L, while Ksp is a unitless equilibrium constant.

What is the effect of entropy on spontaneous solutions?

Solutions will occur if energy of solution formation is lowered or if increased entropy results from spreading out components.

What is the relationship between energy required to break IMFs and energy released during solute-solvent interactions?

If energy released is greater than energy required, the substance will dissolve.

What is an example of an endothermic solution process?

Cold Pack with NH4NO3 (∆Hsoln = +26.4 kJ/mol)

What is an example of an exothermic solution process?

Hot Pack with MgSO4 (∆Hsoln = -91.2 kJ/mol)

What does it mean if a solution is miscible?

The liquids completely mix (e.g., alcohol and water).

What does it mean if a solution is immiscible?

The liquids do not mix (e.g., oil and water).

What is solubility?

The amount that dissolves to form a saturated solution.

What factors affect solubility?

pH, other ions in solution (common ions), and temperature.

How is the solubility of Ca2+ related to the solubility of the compound?

[Ca2+] must be 3 times the solubility of the compound.

How is the solubility of PO43- related to the solubility of the compound?

[PO43-] must be 2 times the solubility of the compound.

What is the Solubility Product Constant (Ksp)?

A constant that relates the solubility of a compound to the concentrations of its ions in solution.

What is the effect of temperature on the solubility of solids?

An increase in temperature usually causes an increase in solubility for solids.

What is the effect of temperature on the solubility of gases?

The solubility of gases decreases with increasing temperature.

What does Henry's Law state?

The amount of gas dissolved is directly proportional to the pressure of the gas above the solution.

What is the formula for Henry's Law?

S = kP, where S is the concentration of dissolved gas, k is the constant for the solution, and P is the partial pressure of the gas.

What is molarity (M)?

Moles of solute per liter of solution.

How do you calculate molarity?

M = moles of solute / liters of solution.

What is molality (m)?

Moles of solute per kilogram of solvent.

How do you calculate molality?

m = moles of solute / kilograms of solvent.

What is the mole fraction?

The number of moles of one component divided by the total number of moles in the solution.

What is the formula for percent concentration by mass?

% by mass = (mass of solute / mass of solution) x 100.

What is parts per million (ppm)?

ppm = (grams of solute / grams of solution) x 10^6.

What is parts per billion (ppb)?

ppb = (grams of solute / grams of solution) x 10^9.

What is the dilution formula?

M1V1 = M2V2, where M is molarity and V is volume.

What is the procedure for preparing a diluted solution?

Moles of solute before dilution equals moles of solute after dilution.

What is the relationship between solubility and structural effects?

Polar substances dissolve in polar solvents, while nonpolar substances dissolve in nonpolar solvents.

How does pressure affect the solubility of gases?

The solubility of a gas increases with increasing pressure.

What is thermal pollution?

Higher water temperatures lead to less oxygen dissolved for wildlife.

What is the significance of the Henry's Law constant?

It indicates how much gas can dissolve in a liquid at a given temperature and pressure.

How do you calculate the concentration of a solution?

Concentration can be expressed in molarity, molality, or percent concentration.

What is the effect of chain length on solubility?

As chains of hydrocarbons become longer, solubility in water decreases and solubility in nonpolar solvents increases.

What is the first step in stoichiometry with solution reactions?

Write and balance the chemical equation.

What is the first step in determining the limiting reagent in a chemical reaction?

Determine the moles of each reactant.

What is the purpose of finding the limiting reagent?

To find the amount of product that can be formed.

What is vapor pressure lowering?

It is a colligative property that lowers the vapor pressure of a solvent when a nonvolatile solute is added.

What happens to the boiling point of a solvent when a nonvolatile solute is added?

The boiling point is elevated.

What is Raoult's Law?

PA = XA P°A, where PA is the partial pressure of the solvent's vapor, XA is the mole fraction of the solvent, and P°A is the vapor pressure of the pure solvent.

What is the Van't Hoff factor (i)?

It is a measure of the number of particles a solute produces in solution.

What is the formula for boiling-point elevation?

DTbp = Kb m i, where DTbp is the increase in boiling point, Kb is the proportionality constant, m is molality, and i is the Van't Hoff factor.

What is the formula for freezing-point depression?

DTfp = Kf m i, where DTfp is the decrease in freezing point, Kf is the proportionality constant, m is molality, and i is the Van't Hoff factor.

What is osmotic pressure?

It is the pressure that stops osmosis, calculated using π = M R T i.

What does the term 'colligative properties' refer to?

Properties that depend on the total concentration of solute particles, not their identity.

What is the Tyndall effect?

It is the scattering of light by colloidal particles.

What are the solubility rules for salts of ammonium and alkali metals?

They are always soluble.

What are the solubility rules for phosphates, carbonates, and sulfides?

They are generally insoluble except when combined with ammonium and alkali metal compounds.

What is the solubility rule for chlorides, bromides, and iodides?

They are soluble except when combined with Ag, Hg2+, and Pb.

What happens to the freezing point of a solvent when a nonvolatile solute is added?

The freezing point is lowered.

What is the effect of adding salt to water when cooking pasta?

It raises the boiling point, requiring more energy to boil.

How do you classify sodium carbonate in terms of solubility?

It is soluble.

How do you classify lead sulfate in terms of solubility?

It is insoluble.

How do you classify barium nitrate in terms of solubility?

It is soluble.

How do you classify ammonium phosphate in terms of solubility?

It is soluble.

How do you classify cobalt (II) hydroxide in terms of solubility?

It is insoluble.

What is the effect of a solute on the vapor pressure of a solvent?

It lowers the vapor pressure.

What is the relationship between colligative properties and the number of particles in solution?

Colligative properties depend on the number of solute particles in solution.

What is the formula to calculate osmotic pressure?

π = M R T i, where π is osmotic pressure, M is molarity, R is the gas constant, T is temperature, and i is the Van't Hoff factor.

What is the significance of the proportionality constant Kb?

It depends on the solvent and is used in boiling-point elevation calculations.

What is the significance of the proportionality constant Kf?

It depends on the solvent and is used in freezing-point depression calculations.