Chapter 7: The Mole and Chemical Composition
6.022E23
Avogadro's number
empirical formula
a chemical formula that shows the composition of a compound in terms of the relative numbers and kinds of atoms in the simplest ratio
molecular formula
a chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of the atoms
one on top and one on bottom
explain how avogadro's number can give two conversion factors.
atomic mass is the mass of an atom of a specific isotope. average atomic mass is the weighted average of atomic masses of an element's isotopes
explain the difference between atomic mass and average atomic mass.
molar mass is the value of atomic mass with units
for an element, what is the relationship between atomic mass and molar mass?
multiply number of moles by molar mass to get the mass of a substance in grams
how is molar mass of an element used to convert from number of moles to mass in grams?
6.022E23
how many particles are there in one mole?
mole
the SI base unit used to measure the amount of a substance whose number particles is the same as the number of atoms of carbon in exactly 12 grams of carbon-12
molar mass
the mass in grams of one mole of a substance
percentage composition
the percentage by mass of each element in a compound
average atomic mass
the weighted average of the masses of all naturally occurring isotopes of an element
avogadro's number/1 mol
what conversion factor do you use in converting number of moles into number of formula units?
formula and the molar mass
what do you need to calculate the percentage composition of a substance?
mass ratios of the elements that make up the substance and you can find the empirical formula
what information does percentage composition reveal about a compound?
cesium, carbon, oxygen
what ions are present in cesium carbonate?
CS2CO3
what is the simplest formula for cesium carbonate?
carbon-12
what particular isotope is the basis for defining the atomic mass unit and the mole?
molar mass
what term is used to describe the mass in grams of 1 mol of a substance?
they show equivalent ratios of elements and the percentages are equal
when you calculate the percentage composition of a compound from the both the empirical formula and the molecular formula, why are the two results identical?
