Ch 4: Solids & Liquids

Question 1

Define: crystalline solids

Answer 1

Non-amorphous. Atoms/molecules in these solids form specific crystal patterns on an ordered lattice. Break along predictable lines.

Question 2

What are the 4 types found in crystalline solids?

Answer 2

1) molecular solids
2) metallic solids
3) ionic solids
4) covalent solids

Question 3

Define: molecular solids

Answer 3

Crystalline solids have molecules at the corners of the lattice instead of individual ions. They are soft with low melting point: hydrocarbons, sugar and sulfur.

Question 4

Define: metallic solids

Answer 4

Crystalline solids with a high melting point. Held together by networking type bond where a (+) core atom is held together by a surrounding field of (-) charged electrons. This makes them a good conductor of electricity

Question 5

Define: ionic solids

Answer 5

Crystalline solids form a lattice in which the outside points are made of ions instead of larger molecules. Brittle with high melting points. Do not conduct in the solid state.

Question 6

Define: amorphous solids

Answer 6

Solids which are not crystalline. They had no specific form or standard internal structure. Break into unpredictable shards. Becomes flexible when heated and have no definite melting point.

Question 7

Define: electrolyte

Answer 7

A substance with free ions that allows it to dissolve in water and conduct electricity.

Question 8

Define: covalent solids

Answer 8

Solids/crystals held together by single covalent bonds. High melting/boiling points. Bad electrical conductors.

Question 9

Define: allotropes

Answer 9

Different structural forms of the same element. IE: graphite, diamond, buckminsterfullerene.

Question 10

List the Properties of a Solid

Answer 10

• fixed volume
• definite structure
• cannot be compressed
• held together by molecular, ionic, metallic or covalent bonds
• don’t expand when heated
• amorphous or crystalline in form
• high density

Question 11

Define: precipitate

Answer 11

And insoluble (or saturated) solid that falls out of a solution

Question 12

Define: solution

Answer 12

a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent).

Question 13

Define: saturation

Answer 13

The point at which a the solution of a substance can dissolve no more of the substance (no more reactions can occur).

Question 14

Define: supernate

Answer 14

Supernate is the liquid which remains above the solid produced by a precipitation reaction.

Question 15

Define: mixture

Answer 15

Any solution that can be separated into two or more substances manually. Can be found in two forms: heterogeneous and homogenous

Question 16

Define: heterogeneous

Answer 16

A mixture with physically separate parts and different properties (salt and pepper)

Question 17

Define: homogenous

Answer 17

A mixture with one phase but one which may have more than one component within the sample (salt water). Is the same throughout

Question 18

Define: compound

Answer 18

Substances which can be broken down into simpler compounds/elements

Question 19

What is the density of water?

Answer 19

1 g/mL @ 4 Degrees C

Question 20

How can one know if two liquids will mix?

Answer 20

Liquids of very different densities will not mix.

Exceptions: dense salt water will mix with fresh water bc both are polar. Oil is non-polar and won’t mix with water even at similar densities.

Question 21

List the Properties of a Liquid

Answer 21

• fixed volume
• loose structure
• cannot be tightly compressed
• varying viscosities
• miscible or immiscible
• expand and vaporize when heated
• unequal molecular bonding
• medium density

Question 22

Define: specific gravity

Answer 22

The way to measure the density of a material. Specific gravity = ratio of substances density to density of water.

Question 23

Define: surface tension

Answer 23

A molecule in the middle of a liquid is equally attracted in all directions. At the surface, intermolecular forces are pulled down by gravity. The unequal pull flattens the molecule’s shape and allows it to float on molecules just below them, creating a film.

Question 24

Define: viscosity

Answer 24

A liquids capability to flow (or not flow). The weaker the molecular bonds in a liquid, the more viscosity it has

Question 25

Define: molar heat of vaporization

Answer 25

The amount of energy/heat req to vaporize 1mol of liquid at a constant temp and pressure

Question 26

Define condensation

Answer 26

When vapor turns from gas back into a liquid

Question 27

Define: dynamic equilibrium

Answer 27

When liquid molecules turn to vapor(gas) at the same rate that they condense.

Question 28

Define: phase diagram

Answer 28

A graph for analyzing solid, liquid and gaseous forms of a substance under different pressures and temps.

Question 29

Define: triple point

Answer 29

The temp and pressure on a phase diagram at which three phases of a substance are in equilibrium

Question 30

Define: boiling point

Answer 30

The temp at which vapor pressure equals atmospheric pressure

Question 31

Define: freezing point

Answer 31

The point at which a liquid turns into a solid

Question 32

Define: fractionation

Answer 32

a separation process in which a certain quantity of a mixture (gas, solid, liquid, suspension or isotope) is divided during a phase transition, into a number of smaller quantities (fractions) in which the composition varies according to a gradient.