Then what is it?!
it is a unit of measurement! (a counting unit) that allows chemists to count large quantities such as atoms and molecules by weighing its mass
- mole has same number of particles found in 12g of carbon-12
- Volumes that are equal of different gases have a constant ratio,
For example: Oxygen : Hydrogen 16:1
when they have the same # of particles, the ratio of oxygen to hydrogen will always be 16:1
Avogadro's Hypothesis
Avogadro's hypothesis states that equal volumes of different gasses, at the same temperature and pressure, contain the same number of particles.
- If they have the same number of particles, the mass ratio is due to the mass of particles.
- principle for the relative masses of all atoms are on the periodic table of elements
To understand the hypothesis better, imagine two boxes with oranges in one and apples in the other. You believe that there are equal number of fruits in each box. Not counting the masses of the boxes, you can find the mass of each of the fruit and determine the ratio between the oranges and apples. This is the relative mass since it is a comparison.
Relative Mass
- Relative masses are expressed when comparing it mathematically to the mass of another object.
- Currently, we compare it to the mass of carbon-12 (1 atom is one twelfth the mass of carbon)
Molar Mass
- The molar mass is the mass of ONE mole of particles.
- The molar mass of an element is the mass shown on the periodic table which is expresssed in grams. (same value as molecular mass, formula mass, or atomic mass)
For example: 1 mole of Oxygen = 16.0 g/mol
1 mole of Sodium = 23.0 g/mol
1 mole of CO = 28.0 g/mol
* All of these have the same number of particles.
- Molar atomic mass is the mass of 1 mole of that element.
- "Grams per mole" is the unit for molar mass.
Atomic Mass
- The mass of 1 atom of the element in amu (u)
eg. atomic mass of Iron (Fe) is 55.8u
Formula Mass
- Total mass of all atoms in the formula of an ionic compound
- in atomic mass units (u)
For example: Manganese Oxide
Mn O
54.9 + 16.0
MnO = 70.9 u
Moledular Mass
- All atoms of a formula in covalent compound.
For example: Nitrogen Oxide
N O
14.0 + 16.0
NO = 30.0 u
Avogadro's Number
Do you want Avogadro's number?!
- Well it's....
6.022 × 1023 = particles per mole * memorize it!
- This is the number of particles in 1 mole of any amount of substances.
How big is it?
Have Avogadro's number of pennies placed in a rectangular stack of about 6m by 6m at the base and it would stretch 9.4 x 1012km and extend outside of our solar system. It'd take light approximately a year to travel from one end of the stack to the other!! That's a LOT of pennies!!
Now that you learned about mole, you should learn the mole song!
You will love it...
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