the mole Flashcards
What is a mole?
a unit of measurement that measures the number of particles in a substance
also the number of carbon 12 atoms in 12 grams of of carbon 12
What is avogadros number?
6.022*10^23 or the number of atoms in 12 grams of carbon 12
1 mol of carbon 12 has how many atoms?
6.022 * 10^23
What is molar mass?
The mass in grams of 1 mol of units of a substance (or grams/mol)
What is atomic mass?
The mass of a single atom in atomic mass units.
What is amu?
a unit of mass equal to 1/12 of the mass of one carbon 12 atom
How are the molar mass and avogadros number used together?
To find the mass of a single atom in grams
What is the mass of a single atom of Sodium? How did you figure that out?
3.818 the molar mass of sodium is 22.99 g/mol avogadros number is 6.022*10^23 divide the weight in grams of a mol of sodium atoms by a mol to get the answer so 22.99/6.022*10^23
What is the equation to find the mass of a single atom (atomic mass) of an element?
divide the weight in grams of a mol of the substance’s atoms by a mol to get the answer
so
grams of the substance/6.022*10^23
what is molecular mass?
The sum of the atomic masses in the molecule (so for H2O, add the atomic masses for 2 hydrogen atoms and 1 oxygen atom). It is calculated in amu
Why do scientists calculate percent composition by mass?
to find the purity of a compound or the amount of all of the different elements
How do you find the percent composition by mass?
((number of atoms of the element in one mol of the compound x molar mass of the element)/molar mass of the compound) * 100%
Difference between molar mass and atomic mass?
Molar mass is the mass of one mole of a substance. Atomic mass is the mass of one individual unit of a substance.
How is the mass percentage of an element in a compound calculated?
(total molar mass of the element in the compound)/molar mass of the compound * 100%
