Week 1

Question 1

Hydrogen bond

Answer 1

A bond made between a hydrogen molecule (acceptor) and a molecule with high electronegativity like oxygen, fluorine, or nitrogen (donor).

Question 2

Acceptor

Answer 2

A hydrogen molecule bonded to a highly electronegative molecule which will give the hydrogen a partial positive charge.

Question 3

Donor

Answer 3

A highly electronegative molecule that has a partial to full negative charge

Question 4

Lone electron pairs

Answer 4

Lone electron pairs occur when a bond is not formed with another atom. These electrons reside in the valence shell

Question 5

Dipole (moment)

Answer 5

A dipole moment occurs when a molecule or atom has an area of higher electronegativity as compared to an other area. This uneven sharing of electrons causes a dipole or a direction of stronger electron presence to occur. This makes one end more positive and one end more negative

Question 6

Dielectric constant (permittivity)

Answer 6

This concept applies to how well a molecule can align itself charge wise if an electric field is added. The ions align themselves in the same direction. Something with high permittivity is better able to align itself in one direct and can conduct currents better

Question 7

Triple point

Answer 7

This is the point where all three states of matter exist in the same point in time

Question 8

Equilibrium content

Answer 8

Describes a hygroscopic material or a material that is holding on to moisture where it is also surrounded by air. It is neither gaining nor losing moisture. This depends on the relative humidity and temperature and the material

Question 9

Tetrahedral

Answer 9

The is a four directional shape of the molecular electron. It is the bonding pattern of water molecules, this allows for equal numbers or donors and acceptors

Question 10

Hexagonal ice structure

Answer 10

This is the structure that ice creates when it freezes. The tetrahedral lattice structure extends and rotates to for layers of hexagons

Question 11

Mixture model

Answer 11

This is the model that describes water molecules in that there are bulky clusters of water molecules that have hydrogen bonds similar to that of conventional water or ice and in addition to this, there are more dense species in between the bulky cluster. This theory gives liquid water more density because there are more molecules but the same 85% of hydrogen bonds retained from the frozen state

Question 12

Interstitial model

Answer 12

The interstitial model is a mixture of the continuum model and the mixture model. This theory describes water as having the same bonds as with ice, with little distortion, but with free un-bonded water molecules filling in the interstitial space

Question 13

Pressure shift freezing

Answer 13

If you bring food to a specific pressure, (where the pressure is high and the freezing point is depressed fairly significantly), and then you suddenly release that pressure, the freezing point will increase suddenly and the food will be frozen super quickly. This is what happens with freeze drying?

Question 14

Reverse thawing

Answer 14

With increased pressure, the freezing temperature is decreased. This means if something is held at the same temperature that it was frozen in, but much higher pressure is added, the freezing temperature will go down and the food will actually thaw at the same temperature.

Question 15

Continuum model

Answer 15

This model describes liquid water density by saying that the bonds that were formed with solid ice are still there, they are just compressed in some areas. The bonds are distorted rather than broken. The corset model