Chem Unit Three (CH5&6)

Pressure

Force per unit area exerted against a surface

760

1 atm = ____mm hg

760

1 atm = ____ torr

101,325

1 atm = ____ Pa

Manometer

Measures the pressure of a gas sample

Combined Gas Law

What is this equation?

Standard Pressure and Temperature (STP)

A set of reference conditions where temperature is 0°C (273.15 K) AND pressure is 1 atm.

22.4 Liters

At STP, 1 mole of any gas will have a volume of _____

Ideal Gas Law

PV = nRT

PV = nRT

What is the Ideal Gas Law equation?

Partial Pressure

The pressure that a particular gas would exert if it were alone in the container

Dalton’s Law of Partial Pressure

For a mixture of gases in a container, the total pressure exerted is the sum of the pressures that each gas would exert if it were alone.

P_Total = P_A + P_B + P_C +….

What is the equation for Dalton’s Law of Partial Pressures?

1. Gases consist of particles constantly moving through space in random directions at various speeds.

2. Gas particles have no volume.

3. There are no attractive forces between gas particles.

4. The average kinetic energy of gas particles is proportional to the temperature in kelvins.

5. Molecular collision are elastic; when molecules collide they may exchange Kinetic energy, but the total kinetic energy remains constant.

6. Molecules collide with the walls of their container; these collisions constitute the pressure of the gas.

What are the 6 assumptions of Ideal Gas Kinetic Molecular Theory? (Long Answer)

low pressures and high temps

Gas behavior is closest to ideal at ___________

Intermolecular Forces (IMF)

Attractive forces that exist between molecules.

Intermolecular Forces (IMF)

The strength of ___________ between molecules determines whether any sample of matter is a gas, solid, or a liquid.

Condensation

Gas state to a liquid state

Solidification

Liquid state to a solid state

London Dispersion Forces

Intermolecular Forces (IMF) that exists as a result of instantaneous dipoles/temporary polarization.

Dipole-Dipole Interactions

Intermolecular Forces (IMF) that come from the electrostatic attraction between oppositely charged ends of neighboring dipoles.

Hydrogen Bonding

Intermolecular Forces (IMF) which consists of noncovalent force of attraction between the partial positive on a hydrogen bonded to a N, O, or F and the partial negative charge from a long pair on a nearby N, O, or F.

(0.0821 LxAtm/molxK)

What is the ideal gas constant?

True

True or False: All molecules have dispersion forces?

very high

Ionic bonds have _______ energy

very weak

London dispersion forces have _______ energy

Surface Tension

Resistance of a liquid to an increase in its surface area

Kinetic

______ energy increases as temperature increases

Vapor Pressure

The partial pressure of the vapor in equilibrium with the liquid

Boiling Point

The temperature at which the vapor pressure of a liquid equals the atmospheric pressure

Normal Boiling Point

The temperature at which the vapor pressure of a liquid equals 760 mmHg

1. Nature and strength of the intermolecular forces

2. Molecular size and shape

What are the 2 factors affecting Boiling Point?

Phase

Any part of a system that looks uniform throughout

Phase Change

A change from one physical state to another

Condensation

Gas ——> liquid

Evaporation or vaporization

Liquid ——> Gas

Deposition

Gas —→ Solid

Sublimation

Solid —→ Gas

Crystallization, solidification, or freezing

Liquid —→ Solid

Melting or Fusion

Solid —→ Liquid

Sublimation curve

The curve that represents the boundary between solid and gas

Fusion Curve

The curve that represents that boundary between solid and liquid

Vaporization Curve

The curve that represents the boundary between liquid and gas

Triple Point

When the 3 curves meet on the phase diagram

Critical Point

The point at which the boundary between liquid and gas blurs

Solution

A homogenous Mixture

Solute

A minor component being dissolved

Solvent

A major component doing the dissolving (usually water)

Aqueous Solution

A solution in which the solvent is water

Solubility

The maximum amount of a solute that dissolves in a given amount of solvent at a given temperature.

Dilute

Weak; little solute dissolved in solvent

Concentrated

Strong; Lots of solute dissolved in solvent

Saturated Solution

Solution with the maximum amount of solute dissolved

Unsaturated Solution

Solution with less than the maximum amount of solute dissolved

Supersaturated solution

Solution with more than the maximum amount of solute dissolved

1. Nature of the solvent and the solute

2. Temperature

3. Pressure

What are the 3 solubility factors?

Percentage (%)

Concentration is expressed as a ______

Parts per million (ppm) or parts per billion (ppb)

For very dilute solutions, concentration can be expressed in ______ or _______

1. Weight of solute per weight of solution (w/w)

2. Volume of solute per volume of solution (v/v)

3. Weight of solute per volume of solution (w/v)

What are the terms in which concentration can be caluclated?

Molarity = (Mol solute/L solution)

What is the equation for molarity?

M1V1 = M2V2

What is the equation for dilution?

Electrolyte

A solution that has dissolved ions in it and can conduct electricity

Nonelectrolyte

A solution that cannot conduct electricity

Strong electrolyte

Ionic compounds fully ionize

Weak electrolyte

Ionic compounds only partially ionize

Polar

_____ covalent molecules dissolve in water

Nonpolar

______ covalent molecules do NOT dissolve in water

Colloid

A solution in which the solute particle diameter is between 1nm and 1000nm

Solutions

• Particle size: 0.1 - 1.0

• Filterable with paper: No

• Homogenous: Yes

• Settles on standing: No

• Behavior to light: Transparent

Colloids

• Particle size: 1-1000

• Filterable with paper: No

• Homogenous: Borderline

• Settles on standing: No

• Behavior to light: Tyndall Effect

Suspensions

• Particle size: Greater than 1000

• Filterable with paper: Yes

• Homogenous: No

• Settles on standing: Yes

• Behavior to light: Translucent or opaque

Tyndall Effect

Scattering of light by particles in a colloid or fine suspension

Brownian Motion

Random movement of particles suspended in a fluid or other medium

Colligative Property

A property that depends on the number of particles dissolved in the solution, but not on the type of particles

1. Freezing Point Depression

2. Boiling Point Elevation

3. Osmosis

What are the 3 important Colligative Properties

ppm = (solute/solution) x10⁶

What is the equation for ppm?

ppb = (solute/solution) x 10⁹

What is the equation for ppb

% = (solute/solution) x 100

What is the equation for percentage of concentration?

Increases

As temperature increases, solubility of solids in liquids _______

Decreases

As temperature increases, solubility of gas in liquids _______

Increases

As pressure increases, solubility of gases in liquid ________

(P1 V1/n1 T1) = (P2 V2/n2 T2)

What is the combined Gas Law equation

Fully Ionized

What level of Ionization?

Partially Ionized

What level of Ionization?

No Ionization

What level of Ionization?