objectives redo!

Between primary and secondary bonds which is stronger and why?

Primary bonds because they have a strong/stable structure and high melting points, whereas secondary bonds have weaker attractions between molecules, resulting in a lower melting point

List the primary bonds

• ionic

• covalent

• metallic

List the secondary bonds

• hydrogen

• permanent dipole

• temporary dipole

Which is the strongest bond of the secondary bonds

Hydrogen

List characteristics of solids

• rigid, amorphous, or crystalline

• has a space lattice that resists forces

List the characteristics of liquids

• no set melting point

• molecules have no set arrangement

• takes shape of container

List characteristics of gas

• fills entire shape/space of container

• molecules have v. loose arrangement

How much mass is in each space

Density

Which type of structure can allow for more molecules in a given space = more dense object

Crystalline

If there is more mass in volume A and less mass in volume B and both occupy the same amount of space, which is more dense

Volume A

The material’s ability to resist scratching

Hardness

Why is hardness important in DM

Higher hardness rating decreases abrasion of the material

Ability of a material to deform when force is applied and return to OG shape when removed

Elasticity

When would we care about a substance’s ability to deform and then go back to its original shape?

Impressions or mouthguards

What is the difference between elasticity and plasticity

Elasticity: temporary

Plasticity: permanent

Material’s resistance to elastic deformation, how difficult it is to bend/deform material

Stiffness

Why is stiffness important in dentistry

To withstand biting forces

The greatest amount of stress applied to material, keeping stress+strain directly proportional

Proportional limit

Ability of material to deform under tensile stress w/ out fracturing

Ductility

“can be pulled/stretched without breaking” describes what

Ductility

Material’s ability to deform under compressive forces w/ out fracturing

Malleability

“Can be pressed/hammered w/ out breaking” describes what property

Malleability