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The Mole I (Notes)
Chemistry
If we look at the reaction:
 4NO + 6H2O
4NH3 + 5O2 
we could say that 4NH3 molecules react with 5 O2 molecules to produce ____
NO molecules and ____ H2O molecules.
One dozen represents ______ of something. We could also say that 4 dozen
NH3 molecules react with 5 dozen O2 molecules to produce _____ dozen NO
molecules and _____ dozen H2O molecules.
In reality, it is virtually impossible to obtain 1 molecule or even 1 dozen
molecules of something because a molecule is so small. Instead, chemists use a
much larger value, called a ____________.
We have spent some time looking at the atomic mass unit for elements, which is
when the mass of an atom is expressed in terms of a carbon-12 atom, with 1
atomic mass unit being equal to 1/12 the mass of a carbon-12 atom. A mole of
something is defined as the number of atoms in exactly 12.0 grams of carbon
12. 1 dozen represents ______ of something. One mole represents
____________________ of something. The atomic mass unit of any element in
grams represents one mole (__________________ atoms) of the element. For
example, sodium, Na, has approximately 23 amu. Therefore, 1 mole ( 6.02 x
1023 atoms ) of sodium has a mass of _______ grams. Oxygen has
approximately 16 amu. Therefore, 1 mole of oxygen atoms has a mass of
_______ grams. The oxygen molecule, O2, has a value of 2 x 16 = ______ amu.
So, 1 mole (________________) O2 molecules has a mass of _______ grams.
How many grams of water will represent 1 mole of water molecules?
The number 1 mole, ___________________, is called ___________________
Number. It is difficult to comprehend the size of 1 mole. Our book mentions
that a pile of 1 mole of notebook paper would extend beyond our solar system,
and that 1 mole of pennies (a penny is 1/100 of a dollar) is enough to give every
person on earth 1 million dollars every day for over 1000 years. Yet, if we have
just 12 grams of carbon, that sample will contain 1 mole of atoms.
We will be doing many conversions between moles, number of “things”, and
masses. The molar mass of something is how many grams there are in 1 mole
of the substance. Some types of problems we often deal with are:
changing grams to moles
example: How many moles are there in 25.2 grams of H2SO4
Changing moles to grams
example: What is the mass of 7.3 moles of NH3?
Finding how many units of something:
example: How many atoms of aluminum are there in 53.5 grams of aluminum?
example: How many water molecules are there in 60.2 grams of H2O?
Finding the mass of a number of something
example: What is the mass of 5.35 x 1025 molecules of O2?
The Mole I (Assignment)
Chemistry
1.) Find the molar mass (how many grams there are in one mole) for the
following:
a.) CO
b.) Ca(NO3)2
2.) Compute how many moles there are in the following:
a.) 63.2 grams of ammonia, NH3.
b.) 100. grams of Fe.
3.) Compute the mass of the following samples:
a.) 3.5 moles of glucose, C6H12O6.
b.) 6.2 moles of table salt, NaCl.
4.) Compute the number of molecules of each substance
a.) 6.3 moles of water molecules
b.) 29. grams of water
5.) How many moles of hydrogen atoms are there in 6.0 moles of water
molecules?
6.) How many moles of oxygen atoms are there in 6.0 moles of water
molecules?