3.2 - Introducing the Mole - The Central Unit of Chemistry Flashcards
What form of mass is indicated for each element on the periodic table?
Relative Atomic Mass.
When you have several elements in the amount of their respective relative atomic masses, each element would have the same number of ______?
Particles.
The mole is a unit of what?
Magnitude (quantity).
What do you call the SI unit for the quantity of atoms in exactly 12 g of pure carbon-12?
The mole.
What is the unit symbol for the mole?
mol
Is a mole an estimated measurement or a “counted value”
Estimate, affects sig figs.
What is the name for the number of things in one mole?
Avogadro’s constant.
What is the value of one mole?
6.02 x 10 ^23
What are the two possible conversion factors for avogadro’s constant?
1 mol/6.02 x 10^23 items or 6.02 x 10^23 items/1 mol
What do you call the mass of one mole of substance (particles can be atoms, ions, or molecules)
Molar mass.
What is the unit symbol for molar mass?
g/mol.
Why is molar mass unique to every substance?
atoms/molecules range in size/mass, therefore a mole of them will have different masses depending on what the particles are.
How do you find the molar mass of an element on the periodic table?
Take its relative atomic mass and assign the unit g/mol as relative atomic mass = molar mass.
How do you find the molar mass of a compound?
Calculate the molar mass of a compound by adding up the molar masses of its individual atoms.
What do you need to know to calculate a compound’s molar mass?
- Which elements are present.
- # of atoms in each element.
- Each element’s molar mass.
When calculating a compound’s molar mass, do you use the sig fig rules for addition or multiplication?
Addition (you are adding their values all up for your final answer).
Molar masses should be to what decimal place?
1 decimal place.
What is the most common mistake in calculating a compound’s molar mass?
Miscounting the atoms in each element (subscripts of bracketed symbols apply to everything in the brackets).
When finding the molar mass of a hydrate, do you include the water portion of the compound?
Yes, because it’s molecules are considered part of the compound.
What is the relationship between mass and moles of a substance?
1 molar mass g = 1 mol
What are the conversion factors for molar mass and moles?
molar mass g/1 mol or 1 mol/molar mass g
Which part of the mass/mole conversion factor is constant and what changes based off the substance?
1 mole is constant, the molar mass changes with each substance.
