1. CONCURRENT ENROLLMENT
CHAPTER 6
CONCURRENT ENROLLMENT

2. HYDRATE Sodium carbonate decahydrate = Na2CO3 • 10H2O
A hydrate is a compound that has a specific number of water molecules bound to its atoms.
The number of water molecules associated with
each formula unit of the compound is written following a dot.
Sodium carbonate decahydrate = Na2CO3 • 10H2O

3. When heated, water molecules are released from a hydrate leaving an anhydrous compound.
To determine the formula of a hydrate, find the number of moles of water associated with 1 mole of hydrate
Weigh hydrate.
Heat to drive off the water.
Weigh the anhydrous compound.
Subtract and convert the difference to moles.
The ratio of moles of water to moles of anhydrous compound is the coefficient for water in the hydrate.

4. MATTER Solids have a definite shape and volume
Liquids have a definite volume
Gases will fill a container completely
Compressibility
The change in volume of a sample resulting from a pressure change
Occurs only in gases
Thermal expansion
The change in volume of a sample due to a change in temperature

5. KINETIC THEORY Kinetic energy KE = 1/2mv2 Kinetic theory
Matter is composed of tiny particles called molecules
The particles are in constant motion (have kinetic energy
The particles have potential energy as a result of attracting or repelling each other
The average particle speed increases as the temperature increases
The particles transfer energy form one to another during collisions in which no net energy is lost from the system
Potential energy
Energy a particle has resulting from attractive or repulsive forces

6. CONTINUED Cohesive force
Attractive forces between two particles(potential energy)
Disruptive force
Force resulting from molecular motion (kinetic energy)
Solid
high density (particles close together), definite shape, small compressibility (particles are so close they cannot be pushed together), very small thermal expansion
Liquid
High density (particles close together), indefinite shape, small compressibility (particles are close, cannot be pushed together), small thermal expansion
Gas
Low density (particles widely separated), indefinite shape, large compressibility (mostly empty space, they can be pushed together), moderate thermal expansion

7. GAS LAWS
Mathematical relationship that describes the behavior of gases
Pressure
Standard pressure
1 atm or 760 mmHg of mercury or 760 torr
Learning check pg 176
Absolute zero
Where all motion stops, a value of 0 on the Kelvin scale, different from Celsius by 273
Learning check pg 178

8. COMBINED GAS LAWS Boyle’s law Charles’s law Combined gas law
Law the describes the pressure, volume, and temperature behavior of a gas at constant moles
P1V1 = P2V2
T T2
All other laws can be found in this equation
Learning check pg 182

9. IDEAL GAS LAW Avogadro’s law
In a gas if the same volumes are at the same temperature and pressure they will have the same number of moles
Standard conditions (STP)
1.00 atm and 0 oC
Ideal gas law
PV = nRT
P = pressure (in atm); V = volume (in L); n = number of moles; R = constant, L.atm/mol.K; T = temperature (in Kelvin)

10. DALTONS AND GRAHAM’S LAW
Partial pressure
Total pressure exerted by a mixture of gases is equal to the sum of all the partial pressures
Effusion
Gas escapes through a small hole
Diffusion
Gases spontaneously intermingle
Graham’s law
Effusion rate A = (molecular mass of B)1/2
Effusion rate B (molecular mass of A)1/2

11. EVAPORATION AND BOILING
Endothermic process of a liquid turning into a gas
Condensation
Exothermic process of a gas turning into a liquid
Vapor pressure
Molecular mass and how polar a compound is will affect the vapor pressure
Smaller masses and nonpolar compounds have more vapor pressure
Boiling point
Temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure
Boiling points can be raised by increasing pressure

12. SUBLIMATION Sublimation
Endothermic process of a solid turning into a gas
Carbon dioxide or iodine solid
Melting point
Temperature at which a solid turns into a liquid ( the solid and liquid has the same vapor pressure)
Decomposition
A chemical reaction occurs due to heating
Specific heat
Amount of energy required to raise the temperature of 1g of substance exactly 1oC
Heat = (sample mass)(specific heat)(change in temperature)

13. HEAT
Heat of fusion
Amount of energy required to melt 1g of solid at constant temp.
Heat of vaporization
Amount of energy required to evaporate 1g of liquid at constant temp.