Ch 10 chem

What is surface tension?

A force that tends to pull adjacent parts of a liquid's surface together. •This force results due to the attractive forces between the particles in the liquid.

What is sublimation?

Change of state from a solid directly to a gas.

What is a crystalline solid?

Crystalline solids exist as single crystals or as groups of crystals fused together. •The total three-dimensional arrangement of particles of a crystal is called a crystal structure. •The arrangement of particles in the crystal can be represented by a coordinate system called a lattice.

What are some physical properties of gases?

Gases expand to fill their containers, have a fluid nature, low density, can be compressed, diffuse and effuse - move in small hole spray perfume .

Why do gases have a low density?

Gases have very low densities because their particles are so far apart. •Low mass and large volume lead to small densities.

Explain the fluidity of a gas

Gases have very weak attractive forces. •Gas particles glide easily past one another. •Because gases flow from one point to another they are called fluids.

What is the structure of ice?

Ice consists of water molecules in a hexagonal arrangement. •The empty spaces between molecules in this pattern account for the low density of ice.

What is an ionic crystal?

Ionic crystals consist of positive and negative ions arranged in a regular pattern. •The strong binding forces between the positive and negative ions result in high melting points for this type of solid.

Why do solids have a high density?

Particles are tightly packed together in a given space.

What are some characteristics of the solid phase?

Particles of a solid are more closely packed than those of a liquid or a gas. •Attractive forces in a solid are very strong which gives the solid a rigid shape. •The particles move in a slow, vibratory motion. •Solids have a definite shape and volume.

What is effusion?

Process by which gas particles pass through a tiny opening

What is the diffusion of gas?

Spontaneous mixing of the particles of two substances caused by their random motion.

What is boiling point ?

Temperature at which the equilibrium vapor pressure of the liquid equals the atmospheric pressure.

What is the molar enthalpy of vaporization?

The amount of energy as heat that is needed to vaporize one mole of liquid at the liquid's boiling point at constant pressure.

What is a crystal structure?

The arrangement of atoms, ions, or molecules in a regular way to form a crystal.

What is deposition?

The change of state from a gas to a solid. •The reverse of sublimation.

What is melting?

The change of state in which a solid becomes a liquid by adding energy as heat or changing the pressure.

What are covalent molecular crystals?

The crystal structure of a covalent molecular structure consists of covalently bonded atoms held together by intermolecular forces. Give some examples of amorphous solids: Glass asphalt

What is freezing point?

The normal freezing point is the temperature at which the solid and liquid are in equilibrium at 1 atm (760 mm Hg) pressure.

What is equilibrium vapor pressure?

The pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature.

What is condensation?

The process by which a gas changes to a liquid.

What is the melting point?

The temperature and pressure at which a solid becomes a liquid.

What is evaporation?

•. Process by which particles escape from the surface of a nonboiling liquid and enter the gas phase. -- weak attractive forces faster size of container doesn't matter

What are the basic assumptions of the kinetic-molecular theory?

•1. Gases consist of large numbers of tiny particles that are far apart relative to their size.- trying to fill their container 2. Collisions between gas particles and between particles- doesn't change speed as if it didn't happen- air hockey, no friction •3. Gas particles are in continuous, rapid, random motion.- so we can breathe new air each time 4. There are no forces of attraction between gas particles - so all oxygen won't clump in corner unlike solid/liquid 5. The temperature of a gas depends on the average kinetic energy of the particles of the gas. - speed up with heat

What is equilibrium?

•A dynamic condition in which two opposing changes occur at equal rates in a closed system.

What is an ideal gas?

•A hypothetical gas that perfectly fits all the assumptions of the kinetic-molecular theory.

What are some characteristics of the liquid state?

•A liquid has a definite volume and takes the shape of its container. •The particles of a liquid are in constant motion but move slower than the particles in the gas state. •The attractive forces between the particles in a liquid are much stronger than those in the gas state. •Liquid particles are more ordered than the particles of gas due to their stronger intermolecular forces.

What are supercooled liquids?

•A liquid that is cooled below its normal freezing point without solidifying.

What is the difference between an ideal and a real gas?

•A real gas is a gas that does not behave completely according to the assumptions of the kinetic-molecular theory.

What is a fluid?

•A substance that can flow and take the shape of its container.

What is a phase?

•Any part of a system that has uniform composition and properties.

Why are liquids relatively incompressible?

•As mentioned before, liquid particles are much closer together than gas particles - so it is very hard to squeeze them even closer.

What is capillary action?

•Attraction of the surface of a liquid to the surface of a solid.- like trees outside of tube is cohesion like molecules water and solid wood of tree

Why do liquids have a fairly high density?

•Because liquids have particles which are much closer together - their densities are much larger than those of gases.

Examples of capillary action:

•Capillary action is at least responsible for the transportation of water from the roots of trees to its leaves.

Why are gases compressible?

•Gas particles being very far apart can easily be pushed

What is diffusion?

•Gases diffuse readily into one another and mix together due to the rapid motion of the molecules and the empty space between the molecules.

Explain expansion of a gas

•Gases do not have a definite shape or volume. •They always try to fill their entire container.

What force causes this structure?

•Hydrogen bonding forces in water cause this structure.

What are covalent network crystals?

•In network solids, each atom is covalently bonded to its nearest neighboring atoms. •The covalent bonding extends throughout a network that includes a very large number of atoms. •Three-dimensional network solids include: diamond, quartz, graphite, and silicon dioxide (sand). Pictures of network solids Diamonds structure

What is the critical point?

•Indicates the critical temperature and pressure above which the substance cannot exist in the liquid state.

What is the triple point?

•Indicates the temperature and pressure conditions at which the solid, liquid, and gas phases of a substance can coexist at equilibrium.

What is a phase diagram?

•Is a graph of pressure versus temperature that shows the conditions under which the phases of a substance exist. •A phase diagram also reveals how the states of a system change with changing temperature and pressure.

What is the critical temperature?

•Is the temperature above which the substance cannot exist in the liquid state.

Why are liquids able to diffuse?

•Liquid particles move fairly fast - so they can diffuse through other materials. •As the temperature of a liquid increases, they diffuse much more rapidly because the speed of their particles increases.

What are volatile liquids?

•Liquids that evaporate easily.

What is a metallic crystal?

•Metal crystal consists of metal cations surrounded by a "sea" of delocalized valence electrons. •The electrons come from the metal atoms and belong to the crystal as a whole. Draw a sample picture: Plus and minus layer

Why are solids relatively incompressible?

•Particles are so tightly packed - that it is very hard to squeeze them closer together.

Why do solids have a low rate of diffusion?

•Particles have a slow vibratory motion so they move very slowly through another medium.

What is the kinetic-molecular theory?

•Particles of matter are always in motion.

What is vaporization?

•Process by which a liquid or a solid changes to a gas.

What is an amorphous solid?

•Solids which are not arranged in a regular pattern. •Examples of amorphous solids are glass, plastic, etc.

What is normal boiling point?

•Temperature at which the vapor pressure of the liquid equals standard pressure - 1 atmosphere or 760 mm Hg.

What is the molar enthalpy of fusion?

•The amount of energy as heat required to melt one mole of solid at the solid's melting point.

What is boiling?

•The conversion of a liquid to a vapor within the liquid as well as at its surface.

What is the critical pressure?

•The lowest pressure at which the substance can exist as a liquid at the critical temperature.

Why do solids have a definite shape and volume?

•The particles are very close together and have strong attractive forces.

What is freezing?

•The physical change of a liquid to a solid by removal of energy as heat.

What is freezing?

•The physical change of a liquid to a solid.

What is a unit cell?

•The smallest portion of a crystal lattice the shows the three-dimensional pattern of the entire lattice. Draw some examples: Cubes see book and pp

What are the physical properties of water?

•Water is transparent, odorless, tasteless, and almost colorless.