chapter 8
DESCRIPTION
Chapter 8. Molecular & Formula Masses. Atomic mass. The atomic mass is the average mass of an atom. When using atomic masses make sure to round to at least one decimal place. What is the atomic mass of actinium (Ac)?. What is the atomic mass of hydrogen (H)?. - PowerPoint PPT PresentationTRANSCRIPT
Chapter 8Molecular & Formula
Masses
Atomic mass
• The atomic mass is the average mass of an atom.
When using atomic masses make sure to round to at least one decimal place.
What is the atomic mass of actinium (Ac)?
What is the atomic mass of hydrogen (H)?
What is the mass of hydrogen (H2)?
Determine the Molecular Mass of Vitamin AC20H30O
Determine the Molecular Mass of Vitamin AC20H30O
20 x 12.0 = 240.030 x 1.0 = 30.01 x 16.0 = 16.0 = 286.0 amu
Formula Mass
• The formula mass is the mass of an ionic compound.
• An ionic compound is formed from a combination of metals and nonmetals.
• Formulas masses are calculated the same as molecular masses.
Determine the Formula Mass of Calcium PhosphateCa3(PO4)2
Determine the Formula Mass of Calcium PhosphateCa3(PO4)2
3 x 40.1 = 120.32 x 31.0 = 62.08 x 16.0 = 128.0 = 310.3 amu
The Mole
The MoleThe Mole
• A counting unit• Similar to a dozen, except instead
of 12, it’s 602 billion trillion 602,000,000,000,000,000,000,000
• 6.02 X 1023 (in scientific notation)• This number is named in honor of
Amedeo Avogadro (1776 – 1856)Amedeo Avogadro (1776 – 1856), and is called Avogadro’s Number.
The Mole (mol)The Mole (mol)• 1 mole of cookies = 6.02 X 1023 cookies
• 1 mole of cars = 6.02 X 1023 cars
• 1 mole of Al atoms = 6.02 X 1023 atoms
How big is a mole?
• How many cents are in one mole of pennies?
How big is a mole?
• How many cents are in one mole of pennies?
6.02 x 1023¢
How big is a mole?
• How many dollars are in 6.02 x 1023¢?
How big is a mole?
• How many cents are in one mole of pennies?
= $6.02 x 1021
6.02 x 1023¢100¢$1
How big is a mole?• There are about 6.6 billion (6.6 x 109) people on earth.• If we divided the 1 mole of pennies ($6.02 x 1021)
equally among all the people on earth how many dollars would you have?
How big is a mole?• There are about 6.6 billion (6.6 x 109) people on earth.• If we divided the 1 mole of pennies ($6.02 x 1021)
equally among all the people on earth how many dollars would you have?
$6.02 x 1021
6.6 x 109 people = $9.1 x 1011/person
$910,000,000,000 = 910 billion dollars
How big is a mole?
• How many years would it take you to spend your 910 billion dollars if you spent $100,000 per day?
How big is a mole?
• How many years would it take you to spend your 910 billion dollars if you spent $100,000 per day?
$9.1 x 1011
$100,000day
365 daysyear
= 25,000 years
25,000 years agoNeanderthals died out about 25,000 years ago
Homework
• Finish Mole Worksheet “How Big is a Mole”.
• Molecular and Formula Mass Worksheet• Don’t forget to show your work on your
calculations.