Before we delve into the world of AP chemistry, you should probably establish a basic foundation. Have a calculator and periodic table handy!
So what is a mole?
No not that kind of mole!
There you go!
A Mole (abbv. Mol) is a standard measurement unit often used in chemistry.
1 mole contains 6.022 × 10²³, also known as avogadro’s number, small particles (atoms, molecules, etc.).
A mole is a number— very much like how a dozen= 12, the mole is = to 6.022 × 10²³
Why was the mole discovered?
Scientists wanted a way to find the specific amounts of small particles (atoms, molecules, electrons, etc.) using mass.
Why?
Small particles are SMALL, therefore hard to count.
How is the mole used?
On the periodic table, the number underneath the element indicates the Atomic Mass, its unit being the Atomic Mass Unit (amu):
An Amu is 1/12 the mass of carbon-12 isotope, which has 6 protons and 6 neutrons. From that, we know that amu roughly =protons+ neutrons.
Referring back to moles, chemists also use molar mass, or the number of grams for a mole of an element (each element has a different molar mass).
Atomic mass unit (Amu) is numerically the same as molar mass.
So oxygen has 16.00 amu, and it equals to a molar mass of 16.00 g/mol (grams/1 mole)
Molar mass is good for conversions using a method called dimensional analysis.
It is used to convert particles to moles to grams, and vise versa.
How Do We Do Dimensional Analysis?
Grams to moles
i.e:
How many moles are in 30 grams of Oxygen (O)?
Moles to atoms
How many atoms are in 1.875 moles of oxygen?
Molar mass and Avogadro's number are both dimensional analysis tools for conversions. These tools can be used to convert from grams to moles to atoms, or the other way around from atoms, moles, to grams.
How do we do that?
The tools can be used in different forms:
So implementing that in, how many grams are 1.129*10^24 atoms of Oxygen?
30 grams = 1.129 *10^24 atoms Oxygen
The skill of dimensional analysis will be used very often throughout your honors chemistry and AP chemistry courses. We will brush up on it again on the next blog of STOICHIOMETRY.
I hope this helped! Contact me @ scinspiration1@gmail.com if you have any questions :)
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