1. Chapter 14

2. The Mole, Avogadro's Number, and Molecular Mass

3. Atomic Mass Unit, U
By international agreement, the reference element is chosen to be the most abundant type of carbon, called carbon-12, and its atomic mass is defined to be exactly twelve atomic mass units, or 12 u.

4. Molecular Mass
The molecular mass of a molecule is the sum of the atomic masses of its atoms.
For instance, hydrogen and oxygen have atomic masses of u and u, respectively.
The molecular mass of a water molecule (H2O) is:
2( u) u = u.

5. Avogadro's Number NA
The number of atoms per mole is known as Avogadro's number NA, after the Italian scientist Amedeo Avogadro (1776–1856):

6. Number of Moles, n
The number of moles n contained in any sample is the number of particles N in the sample divided by the number of particles per mole NA (Avogadro's number):
The number of moles contained in a sample can also be found
from its mass.

7. Pressure KEY UNITS AT SEA LEVEL 101.325 kPa (kilopascal) 1 atm
760 mm Hg
760 torr
14.7 psi

8. Standard Temperature & Pressure
STP
Standard Temperature & Pressure
0°C K
1 atm kPa
-OR-

9. A. Boyle’s Law P V
PV = k

10. A. Boyle’s Law
The pressure and volume of a gas are inversely related
at constant mass & temp P V
P1V1 = P2V2

11. B. Charles’ Law V T

12. B. Charles’ Law
The volume and absolute temperature (K) of a gas are directly related
at constant mass & pressure V T
V1/T1 = V2/T2

13. C. Gay-Lussac’s Law P T

14. P1/T1 = P2/T2 C. Gay-Lussac’s Law
The pressure and absolute temperature (K) of a gas are directly related
at constant mass & volume P T
P1/T1 = P2/T2

15. D. Avogadro’s Principle

16. D. Avogadro’s Principle
Equal volumes of gases contain equal numbers of moles
at constant temp & pressure
true for any gas V n

17. UNIVERSAL GAS CONSTANT
Ideal Gas Law PV nT V n PV T
= k
= R
UNIVERSAL GAS CONSTANT
R= Latm/molK
R=8.315 J/molK

18. UNIVERSAL GAS CONSTANT
Ideal Gas Law
PV=nRT
UNIVERSAL GAS CONSTANT
R= Latm/molK
R=8.315 J/molK

19. The Ideal Gas Law
An ideal gas is an idealized model for real gases that have sufficiently low densities.
The condition of low density means that the molecules of the gas are so far apart that they do not interact (except during collisions that are effectively elastic).
A gas behaves more like an ideal gas at High Temperature and Low Pressure.

20. The Ideal Gas Law
The constant term R/NA is referred to as Boltzmann's constant, in honor of the Austrian physicist Ludwig Boltzmann (1844–1906), and is represented by the symbol k:
PV = NkT

21. To Be Continued…