mole concept Flashcards
1
Q
define relative atomic mass
A
average mass of one atom of an element relative to 1/12 the mass of an atom of carbon-12
2
Q
name the standard atom
A
- carbon-12
- it is used as a basis of comparison for all other atomic mass measurements
3
Q
expression of atomic mass
A
- expressed in decimal form to 3 significant figures
- average out the stable isotopes of the element
4
Q
define relative molecular mass
A
average mass of one molecule to of that substance relative to 1/2 the mass of an atom of carbon-12
5
Q
expression of molecular mass
A
- add together the relative atomic masses (Ar) of the atoms in the formula
- the relative molecular mass is known as Mr
6
Q
common molecular masses
A
- water (H₂O): 18
- carbon dioxide (CO₂): 44
- carbon monoxide (CO): 28
- methanol (CH₃OH): 32
- ethanoic acid (CH₃COOH): 60
