Test 1 Review

Crystals

100

What are some examples of network covalent bonds?

Diamond, Graphite, etc.

200

What are metallic solids?

A type of network covalent solid

300

What are molecular solids?

Covalently bonded with long range order (type of crystalline solids)

400

Copper crystallizes in a face-centered cubic (FCC) lattice structure. Calculate the net number of atoms that belong strictly to one FCC unit cell.

4 atoms per unit cell  

1. (8*1/8) = 1 + (6*1/2) = 3 

2. 1 + 3 = 4

500

Polonium crystallizes in a Simple Cubic (primitive) lattice structure. Calculate the net number of atoms belonging strictly to one simple cubic unit cell.

1 atom per unit cell

Equations

100

You dissolve 3.0 mol of glucose in 2.0 kg of water.

What is the molality?

m = mol solute / kg solvent

m = 3.0 / 2.0

m = 1.5 m

200

A substance has ∆H_trans = 10.0 kJ / mol and ∆S_trans = 20.0 J / mol

What is the transition temperature?

T_trans = ∆H_trans / ∆S_trans

10 kJ => 10,000 J

T= 10,000 / 20 

T = 500 K

300

How much heat is required to heat 2.0 mol of a substance with a molar heat capacity of 10 J/(mol·K) from 20°C to 30°C?

q = nC_m∆T

n = 2.0 mol

∆T = 30 - 20 = 10 degrees C

q = (2.0) (10) (10)

q = 200 J

400

Calculate ΔG:

ΔH=20 kJ 

T=300 K

ΔS = 0.050 kJ / K

ΔG = ΔH - TΔS

= 20 - (300)(0.050)

ΔG = 5 kJ

500

A solution has K_f = 2.0 degrees C / m

and m = 0.50 m

What is the freezing point charge?

ΔT_fus = -K_fmi

ΔT = -(2.0)(0.50)(1)

= -1.0 degrees C

Phases

100

What is the process of solid turning into gas?

Sublimation

200

What is viscosity?

resistance of a liquid to a flow

300

What type of slope does the liquid phase diagram have?

Negative

400

Describe the difference between melting point and boiling point

Melting point - solid => gas

Boiling point - liquid => gas

500

What is the difference between enthalpy and entropy?

Enthalpy (total heat)

Entropy (randomness)

Conductors

100

What's the difference between semiconductors and insulators?

Semiconductors: conduct electricity

Insultators: blocks flow of electrical current (no doping)

200

What are superconductors?

Conductors with zero resistance

300

What is critical temperature?

Highest temperature at which a substance can still exist as a liquid 

400

What is the relationship between conductivity and temperature?

Porportional

500

What are the two types of doping?

P- type : positive holes (spaces without electrons) added to semiconductor

N- type: negative electrons added to semiconductor

Random

100

How are intermolecular forces and vapor pressure related?

Inverse

200

What is deposition?

Gas => solid

300

What is the opposite of vaporization?

Condensation

400

What is the difference between molarity and molality?

M = mol / L 

m = mol / kg

500

Supersaturated vs saturated solution

Supersaturated: more solute than can be dissolved

Saturated: max of amount of solute dissolved