General Chemistry (an almagam of ideas)

Question 1

What is the Clausius-Clapeyron equation?

Answer 1

Question 2

When solving the Clausius-Clapeyron equation for P₂, which permutation do we use?

Answer 2

Question 3

When solving the Clausius-Clapeyron equation for ΔH_vap what permutation do we use?

Answer 3

Question 4

When using the Clausius-Clapeyron equation, which gas constant do we use?

What are the units of this constant and why do we use it?

Answer 4

R = 8.3145 J/mol·k

We use this form of the gas constant because it is in units of energy (joules)

Question 5

How do we “undo” a natural log function?

Answer 5

We take the natural antilog function.
if ln(x) = y
then
e^y = x

This is why “e” is in the second flaschard equation: “When solving the Clausius-Clapeyron equation for P₂, which permutation do we use?”

Question 6

What is the boiling point of a liquid?

Answer 6

THe boiling point of a liquid is the temperature at which the vapor pressure equals the external pressure.

Question 7

At what presssure does the normal boiling point of a substance occur?

Answer 7

At atmospheric pressure: 760 mmHg = 760 torr = 1 atm

Question 8

As the external pressure on a liquid increases, the boiling point _______?

Fill in the blank

Answer 8

Increases

Question 9

What is sublimation?

Answer 9

When a substance goes from a vapor state, directly to a solid state.

Question 10

What is the critical point of a substance?

Answer 10

The point at which the densities of the liquid and gas phases become equal.

Question 11

What is the triple point of a substance?

Answer 11

The point at which all three physical phase states exist in equilibrium.

Question 12

What is the van der Waals radius?

Answer 12

The van der Waals radius is one-half the closest distance between the nuclei of two nonbonded atoms.

The van der Waals radius is always larger than the covalent radius.

Question 13

Name the weak intermolecular forces

Answer 13

1. Ion-dipole
2. Hydrogen bondning
3. Dipole-dipole
4. ion-induced dipole
5. dipole-induced dipole
6. London dispersion forces

Question 14

What are the two highest energy intermolecular forces?

Answer 14

Ion-dipole (40-600 KJ/mol) and hydrogen bonding (10-40 KJ/mol).

Question 15

As the strength of intermolecular forces increases, the boiling point _______?

Fill in the blank

Answer 15

Increases

Question 16

What is hydrogen bonding and when does it occur?

Answer 16

Hydrogen bonding is a strong intermolecular force that occurs when a molecule has a hdrogen atom covalently bonded to a small, highly electronegative atom with lone electron pairs.
(i.e. when N,O, or F has a covalently bonded H atom)

An intermolecular hydrogen bond is the attraction between the H atom of one molecule and a lone pair of the N, O, or F atom of another molecule.

Question 17

What are the three common types of ordering in liquid crystal phases?

Answer 17

1. Nematic
2. Cholesteric
3. Smectic

Question 18

What are the different types of cyrstalline solids?

Answer 18

1. Atomic solids - consist of individual atoms held together by only dispersion forces
2. Molecular solids - consist of individual molecules held together by various combinations of intermolecular forces.
3. Ionic solids - exchibit an organized cyrstal structure
4. Network Covalent solids - consist of atoms covalently bonded together in a 3-D network.

Question 19

What are the two types of solids?

Answer 19

There are:
1. Crystalline solids - have well-defined shapes due to orderly arrangement of their particles
2. Amorphous solids - lack orderly arrangement and have poorly defined shapes

Crystals are composed of particles packed in an orderly 3-D array called the crystal lattice.

Question 20

How many hydrogen bonds can water form per molecule?

Answer 20

Four. One hydrogen bond forms per each lone pair on oxygen (2) and each bonded hydrogen atom (2).

Question 21

As the temperature of water increases, how is the viscosity affected?

Answer 21

As the temperature of water increases, the viscosity of water decreases.

Question 22

What is the definition of surface tension?

Answer 22

Surface tension is the energy required to increase the surface area of a liquid. The stronger the forces between the particles the higher the surface tension.

Question 23

Will dispersion forces be stronger for a larger or smaller molecule?

Answer 23

A larger molecule will have stronger dispersion forces. Also, the more polarizable a molecule is (the larger its electron cloud - or the more electrons) the stronger the dispersion forces.

It’s important to note the polarizability correlates closely with the molar mass. For the most part, the higher the molar mass, the more electrons.

Question 24

In chemistry, what is potential energy?

Answer 24

Attractive forces between molecules

Question 25

In chemistry, what is kinetic energy?

Answer 25

The energy associated with the movement of a particle, which tends to disperse particles.

Question 26

What are intramolecular forces?

Answer 26

Bonding forces found within a molecule.

Question 27

Define gas as a physical state of matter.

Answer 27

Gases have high compressability and high flow. They also conform to the shape and volume of a container.

Question 28

Define liquid as a physical state of matter.

Answer 28

Liquids have extremely low compressability and moderate flow ability. They conform to the shape of their container and their volume is limited by their surface.

Question 29

Define solid as a physical state of matter.

Answer 29

Solids have almost no compressability or flow. They maintain their own shape and volume.

Question 30

How do you determine the formal charge of an atom?

What is the equation?

Answer 30

Formal Charge = (V_e^-) - (N) - (B/2)

(V_e^-) = the number of valence electrons for that atom
(N) = the number of unbonded electrons surrounding that atom
(B) = the number of bonded electrons surrounding that atom