Download The Mole Essential Question To what extent is it

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts

Standard Model wikipedia , lookup

Identical particles wikipedia , lookup

Mathematical formulation of the Standard Model wikipedia , lookup

Elementary particle wikipedia , lookup

Minimal Supersymmetric Standard Model wikipedia , lookup

The Mole
Essential Question
To what extent is it advantageous to look at chemical composition in terms of
moles instead of mass?
How do we measure matter?
 Mass
o Buy potatoes by the kilogram, pound, gram, or ounce
 Volume
o Gasoline – gallon, liter
o Liquid medicine – milliliter
 Count
o Soda – 6, 12, 24, or 36 packs
 Sometimes we use specific words to mean a certain amount
o Pair – 2
o Dozen – 12
 Conversion factors
o We use conversion factors everyday
Example – 1 dozen = 12 eggs  this can be set-up like this to be used
as a conversion factor.
The format you use
depends on how you are using the conversion factor.
Example 2 – Apples
Example Problem, if 0.20 bushel is 1 dozen apples and a dozen apples has a mass
of 2.0 kg, what is the mass of 0.50 bushel of apples?
Assume 2.0 kg of apples is 1 dozen and that each apple has 8 seeds. How many
apple seeds are in 14kg of apples?
Mole – 6.02 x 1023 representative particles of a substance
Avogadro’s number
(SI unit for measuring the amount of a substance)
What is a representative particle?
Ionic compound – formula unit
Molecular compound (covalently bonded) – molecule
Ion – ion example Ca+2
Element – atom
1 mole of any substance contains Avogadro’s number of representative particles
Converting # of particles to moles
What is the conversion factor?
Example problem 1:
Magnesium is a light metal used in the manufacture of aircraft, automobile
wheels, tools, and garden furniture. How many moles of magnesium is 1.25 x 1023
atoms of magnesium?
Example Problem 2:
How many moles of 2.17 x 1023 representative particles of bromine?
Converting moles to number of particles
What is the conversion factor?
Example problem 3:
Propane is a gas used for cooking and heating. How many atoms are in 2.12 mol
of propane (C3H8)?
Example Problem 1 Answer:
Example Problem 2 Answer:
Example Problem 3 Answer:
Molar Mass
 On the periodic table the atomic mass of an element is reported in amu.
(atomic mass units).
 Relative to the mass of C-12.
o Why are these not whole numbers?
 Since we cannot use units of amu in the lab, this scale has been converted
to masses measured in grams.
 The mass of an element is expressed in grams/mole. The mass is the
number of grams of 1 mole of that element. Molar mass
Molar mass of a compound
(Also can be called gram formula mass, gram atomic mass, gram molecular
mass, molecular weight)
You need:
The formula of the compound
Atomic numbers of the elements in the compound
Must account for the number of atoms of each element
Example 4:
The decomposition of hydrogen peroxide (H2O2) provides sufficient energy to
launch a rocket. What is the molar mass of hydrogen peroxide?
Molecular formula: H2O2
H = 1.01 g/mol
O = 15.99 g/mol
(1.01 g/mol x 2) + (15.99g/mol x 2) = 34.00 g/mol
2.02 g H + 31.98 g O = 34.00 g/mol