Lecture 2

Question 1

what are the interatomic primary bonds?

Answer 1

ionic, covalent

Question 2

what is an ionic bond, and what are some dentistry-related examples?

Answer 2

an ionic bond is a chemical bond between a metal and non-metal due to electrostatic attraction between an anion and cation; e.g. gypsum and cement

Question 3

what is the bond strength of covalent bonds?

Answer 3

143 kcal/mol

Question 4

what is the bond strength of ionic bonds?

Answer 4

72 kcal/mol

Question 5

what is the bond strength of metallic bonds?

Answer 5

~50 kcal/mol

Question 6

what is the bond strength of hydrogen bonds?

Answer 6

2-10 kcal/mol

Question 7

what is the bond strength of VdWs?

Answer 7

~1 kcal/mol

Question 8

what is thermal energy?

Answer 8

kinetic energy of an atom/molecule; the amount of vibration of a ;cule which is temp dependent; as temp increases, interatomic distance increases

Question 9

Diffusion is a function of temperature and concentration gradient
Temperature = increases kinetic energy/thermal energy = pushes ‘cules away
Concentration gradient—bump into each other

Answer 9

ye

Question 10

what is surface e or surface tension?

Answer 10

The increase in energy per unit area of surface is referred to as surface energy or surface tension

Question 11

define wetting?

Answer 11

The ability of a liquid to maintain contact with a solid surface

Question 12

Metals exhibit high surface energy, thus they interact strongly with liquids

Answer 12

ye

Question 13

study slide 20

Answer 13

ye

Question 14

amorphous materials Characterized with Glass Transition Temperature (Tg), where there is an abrupt increase in the thermal coefficient of expansion

The Tg: a material going from cold to hot suddenly increases in volume; mostly only happens in amorphous solids
Comes before melting point

Answer 14

ye