Lesson 2 Flashcards
Atomic mass is the mass of an atom expressed in atomic mass units or amu.
- 1amu = 1/12 the mass of the carbon - 12 atom
– Another name for the amu is the Dalton (Da)
Atomic mass is the mass of an atom expressed in atomic mass units or amu.
- 1amu = 1/12 the mass of the carbon - 12 atom
– Another name for the amu is the Dalton (Da)
Avogadro’s number may be used to count any kind of particle, including atoms, ions, molecules, electrons, etc.
- it is abbreviated mol
– The mole is the SI (metric) unit for the number of particles (amount) in a sample
Avogadro’s number may be used to count any kind of particle, including atoms, ions, molecules, electrons, etc.
- it is abbreviated mol
– The mole is the SI (metric) unit for the number of particles (amount) in a sample
Scientists needed a common substance to define the mole:
A mole is defined as the number of atons in exactly 12 grams of carbon- 12
Scientists needed a common substance to define the mole:
A mole is defined as the number of atons in exactly 12 grams of carbon- 12
A useful property of a substance is its molar mass
The molar mass of a substance (element or compound) is the mass in grams of one mole in the substance
Molar mass has the unit grams per mole ( g/mol)
A useful property of a substance is its molar mass
The molar mass of a substance (element or compound) is the mass in grams of one mole in the substance
Molar mass has the unit grams per mole ( g/mol)
One-mole quantities of two different substances have different masses for the same reason - the substances have different compositions.
One-mole quantities of two different substances have different masses for the same reason - the substances have different compositions.
Recall that each atom of carbon 12 has a mass of 12 amu
Recall that each atom of carbon 12 has a mass of 12 amu
An atom of hydrogen-1 has a mass approx 1 amu, one twelfth the mass of a carbon-12 atom.
An atom of hydrogen-1 has a mass approx 1 amu, one twelfth the mass of a carbon-12 atom.
The noninteger values occur because the values are weighted averages of the masses of all the naturally occurring isotopes of each element.
The noninteger values occur because the values are weighted averages of the masses of all the naturally occurring isotopes of each element.
the mass of one mole of carbon-12 atoms is 12g.
the mass of one mole of carbon-12 atoms is 12g.
The mass in grams of one mole of any pure substance is called its
The mass in grams of one mole of any purse substance is called its molar mass
The molar mass of any element is numerically equal to its atomic mass and has the units g/mol.
The molar mass of any element is numerically equal to its atomic mass and has the units g/mol.
