3.2 Properties of Solids

Many properties of liquids and solids are determined by the:

Strengths and types of intermolecular forces present

What happens to intermolecular interactions when a substance vaporizes?

Broken

The vapor pressure and boiling point are directly related to the:

Strength of intermolecular interactions

Why are the vapor pressure and boiling point directly related to the strength of intermolecular interactions?

Because intermolecular interactions are broken when a substance vaporizes

Melting points tend to correlate with:

Strength of intermolecular interactions

The relationship between melting points and strength of intermolecular interactions is:

Subtle

Why is the relationship between melting points and strength of intermolecular interactions subtle?

Because the interactions are only rearranged in melting

Particulate-level representations show:

Multiple interacting chemical species

Particulate-level representations are a useful means to communicate or understand how ______ help to establish macroscopic properties

Intermolecular interactions

Particulate-level representations are a useful means to communicate or understand how intermolecular interactions help to establish ______

Macroscopic properties

Ionic solids tend to have high/low vapor pressures

Low

Ionic solids tend to have high/low melting points

High

Ionic solids tend to have high/low boiling points

High

Who do ionic solids tend to have low vapor pressures, high melting points, and high boiling points?

Because of the strong interactions between ions

Why do ionic solids tend to be brittle?

Because of the repulsion of like charges caused when one layer slides across another layer

The repulsion of like charges caused when one layer of an ionic solid slides across another layer of that ionic solid results in ionic solids being:

Brittle

Do ionic solids conduct electricity?

Only when the ions are mobile

When are ions of ionic solids mobile?

When the ionic solid is melted or dissolved in water or another solvent

How are atoms bonded together in covalent network solids?

Covalently

In covalent network solids, the atoms are covalently bonded together into:

A three-dimensional network or layers of two-dimensional networks

Example of a covalent network solid that is a three-dimensional network:

Diamond

Example of a covalent network solid that is composed of layers of two-dimensional networks:

Graphite

Covalent network solids are formed from:

Nonmetals

Types of nonmetal formations into covalent network solids:

Elemental or binary compounds of two nonmetals

Examples of elemental covalent network solids:

Diamond and graphite

Examples of covalent network solids that are binary compounds of two nonmetals:

Silicon dioxide and silicon carbide

Covalent solids have high/low melting points

High

Why do covalent solids have high melting points?

Because of the strong covalent interactions

Texture of three-dimensional network solids:

Rigid and hard

Why are three-dimensional network solids rigid and hard?

Because the covalent bond angles are fixed

Graphite is hard/soft

Soft

Why is graphite soft?

Because adjacent layers can slide past each other relatively easily

Molecular solids are composed of:

Distinct, individual units of covalently-bonded molecules

The distinct, individual units of covalently-bonded molecules of molecular solids are attracted to each other through:

Intermolecular forces

The intermolecular forces that attract the distinct, individual units of covalently-bonded molecules of molecular solids are relatively strong/weak

Weak

Do molecular solids conduct electricity?

No

Why do molecular solids not conduct electricity?

Because their valence electrons are tightly held within the covalent bonds and the lone pairs of each constituent molecule

Molecular solids are sometimes composed of:

Very large molecules or polymers

Are metallic solids good conductors of heat and electricity?

Yes

Why are metallic solids good conductors of heat and electricity?

Because of the presence of free valence electrons

Why are metallic solids malleable and ductile?

Because of the ease with which the metal cores can rearrange their structure

The ease with which the metal cores can rearrange their structures makes metallic solids:

Malleable and ductile

In an interstitial alloy, the malleability and ductility is greater/reduced

Reduced

Why are malleability and ductility decreased in an interstitial alloy?

Because interstitial atoms tend to make the lattice more rigid

Are alloys conductors?

Yes

Why are alloys conductors?

They typically retain a sea of mobile electrons

In large biomolecules or polymers, noncovalent interactions may occur between:

Different molecules or between different regions of the same large biomolecule

Where can noncovalent interactions occur between different molecules or between different regions of the same large biomolecule?

In large biomolecules or polymers

The functionality and properties of large biomolecules and polymers depend strongly on:

The shape of the molecule

The shape of a large biomolecule and polymer is largely dictated by:

Noncovalent interactions

Draw a diagram of pure water in a beaker at room temperature:

H2O molecules in liquid phase are moving at the same / different speed(s)

Different

H2O molecules in liquid phase have a range of values for:

Kinetic energy

H2O molecules in liquid phase have a _____ for kinetic energy

Range of values

In H2O, some of the molecules near the surface have sufficient energy to:

Overcome the intermolecular forces between them

In H2O, some of the molecules near the surface have ______ to overcome the intermolecular forces between them

Sufficient energy

In H2O, molecules near the surface with sufficient energy to overcome the intermolecular forces between them can escape from the ______ phase 

Liquid

In H2O, molecules near the surface with sufficient energy to overcome the intermolecular forces between them can enter the:

Space above the liquid surface

A beaker of water will become dry when:

The sample of water evaporates completely

A beaker of water will ______ when the sample of water evaporates completely

Become dry

Draw diagram of a sample of pure water in a sealed flask at room temperature:

In this diagram showing a sample of pure water in a sealed flask at room temperature, the arrows indicate that molecules undergo:

Evaporation and condensation

In this sample of pure water in a sealed flask at room temperature, a point is reached in which:

Rate of evaporation = rate of condensation

Point at which rate of evaporation = rate of condensation is a state of:

Dynamic equilibrium

During dynamic equilibrium, as long as the temperature remains constant, the number of water molecules in the gas phase remains:

Constant

During dynamic equilibrium, as long as the ______ remains constant, the number of water molecules in the gas phase remains constant

Temperature

During _______, as long as the temperature remains constant, the number of water molecules in the gas phase remains constant

Dynamic equilibrium

During dynamic equilibrium, as long as the temperature remains constant, the _______ remains constant

Number of water molecules in the gas phase

The pressure exerted by a gas in equilibrium with its liquid phase at a given temperature:

Vapor pressure

When comparing two different liquids at the same temperature, the liquid that has a lower vapor pressure should also be the liquid that has a lower/higher boiling point

Higher

The temperature at which the vapor pressure of the liquid is equal to the external pressure surrounding the liquid:

Boiling point

The situation in which the vapor pressure of the liquid is equal to standard atmospheric pressure at sea level:

Normal boiling point

Standard atmospheric pressure at sea level is usually defined as ___ atm

1

Standard atmospheric pressure at sea level is usually defined as ___ torr

760

Draw particulate-level representation of ionic solids:

Draw particulate-level representation of covalent network solids:

Draw particulate-level representation of molecular solids:

Draw particulate-level representation of metallic solids:

Particles in ionic solids:

Positive and negative ions

Particles in covalent network solids:

Atoms

Particles in molecular solids:

Molecules

Particles in metallic solids:

Positive metal cations and valence electrons

Positive metal cations include:

Nucleus and core electrons

Attractions between particles in ionic solids:

Electrostatic attractions between oppositely charged ions

Attractions between particles in covalent network solids:

Covalent bonds between atoms in a large, extended network

Attractions between particles in molecular solids:

Intermolecular attractions between molecules

Attractions between particles in metallic solids:

Attractions between positive metal cations and a “sea” of delocalized, mobile valence electrons

Electrical conductivity of ionic solids:

Does not conduct as a solid, conducts when melted or dissolved in a solvent

Why do ionic solids not conduct as a solid?

Ions cannot move freely

Why do ionic solids conduct when melted or dissolved in a solvent?

Ions can move freely

Electrical conductivity of covalent network solids:

Does not conduct

Why do covalent network solids not conduct?

Valence electrons are localized in covalent bonds

Electrical conductivity of molecular solids:

Does not conduct

Why do molecular solids not conduct?

Electrons are localized in covalent bonds and the particles are neutral molecules

Electrical conductivity of metallic solids:

Conducts electricity 

Do metallic solids conduct electricity as a solid?

Yes

Why do metallic solids conduct electricity as a solid?

Because of the mobile valence electrons

Melting point of ionic solids:

Relatively high

Melting point of covalent network solids:

Relatively high

Melting point of molecular solids:

Relatively low