Chapter 12 --> Solids and modern materials

describe a crystalline solid.

when allowed to cool slowly, the particles in a liquid will arrange themselves to give the maximum attractive forces; resulting in a crystalline solid

what is the arrangement of the particles in a crystalline solid called?

crystal lattice

What is the unit cell of the particles?

the smallest unit that shows the pattern of arrangement

describe unit cells.

three dimensional, repeated over and over to give macroscopic crystal structure

what is each particle in the unit cell called?

lattice point

what is a coordination number?

the number of other particles each particle is in contact with

higher coordination number means _________; therefore, __________________ hold the crystal together

more interaction; stronger attractive forces

what is packing efficiency?

percentage of volume in the unit cell occupied by particles

describe a cubic unit cell.

all 90 degree angles at the corners, the length of all edges are equal, if spherical particles: 1/8 of each corner is within the cube, 1/2 of each face is within the cube, and 1/4 of each edge is within the cube

what is the coordination number of a simple cubic cell?

6

how many atoms are in a simple cubic cells?

1

Simple cubic

what is the coordination number of a body centered cubic cell?

8

how many atoms are in a body-centered cubic cell?

2

body centered cubic

what is the coordination number of a face-centered cubic cell?

12

how many atoms are in a face-centered cubic cell?

4

face centered cubic

describe polymers.

many small units called monomers that link together

give some characteristics of polymers.

chain lengths can be varying, results in a mixture, very large molar masses

Longer chains = ______________

stronger polymers

polar side groups give stronger attraction between polymer chains, making the polymer _________

stronger

straight, unbranched chains can pack together more closely, giving that polymers have a ___________ and therefore _________________

higher density; stronger attraction

if polymer chains are linker together extensively by covalent bonds, the polymer is harder and ______________________________________

more difficult to melt