Chapter 3 - The Mole
what is the mass of 0.252 mole of copper?
0.252 mol Cu/1 x 63.55 g Cu/1 mol Cu = 16.0 g Cu
what is the molar mass of calcium hydroxide [Ca(OH)2]?
1 Ca (40.08 g/mol) + 2 O (16.00 g/mol) + 2 H (1.01 g/mol) = 74.10 g/mol
what is the molar mass of potassium nitrate [KNO3]?
1 K (39.10 g/mol) + 1 N (14.01 g/mol) + 3 O (16.00 g/mol) = 101.1 g/mol
how many objects does one mole equal?
1 mole = 6.022 x 10^23
how many atoms does molar mass contain?
1 mole of atoms
what is the mass of one atom of carbon?
1.00 atom C/1 x 1 mol C/6.022x10^23 atom C x 12.01 g C/1 mol C = 1.99x10^-23 g C
how many oxygen atoms are present in 1.00 mole of oxygen molecules?
1.00 mol O2/1 x 6.022x10^23 molecules O2/1 mol x 2 O atoms /1 O2 molecule = 1.24x10^24 atoms O
how many amu or g/mole does carbon contain?
12.0 amu or 12 g/mole
how many moles of iron does 25.0g of iron represent? (grams Fe to moles of Fe)
25.0 g Fe/1 x 1 mol Fe/55.85 g Fe (molar mass) = 0.448 mol Fe
what is the mass of 3.01 x 10^23 atoms of Na?
3.01 x 10^23 atom Na/1 x 1 mol Na/6.022x10^23 atom Na x 22.99 g/1 mol Na = 11.5 g Na
using avodadro's number, how many moles of silver, Ag, are in 3.01 x 10^22 atoms of silver?
3.01x10^23 Ag atoms/1 x 1 mol Ag/6.022x10^23 atoms = 0.500 mol Ag
what is the mass in grams of 3.50 mole of the element, copper?
3.50 mol Cu/1 x 63.55 g Cu/1 mol Cu = 222g Cu
what does one mole of atoms equal? one mole of molecules? one mole of ions?
6.022 x 10^23 atoms, molecules, ions
what is the molar mass of water?
H2O 1(16.00g/mole) + 2(1.01g/mole) = 18.02 g/mol
what is molar mass written in (unit wise)?
g/mole
on the periodic table, how is amu given/written out?
in g/mole of atom
what three types of substances does the mole apply to?
it applies to atoms, molecules, and ions, symbolizing enough of them to actually be weighed out and counted
which unit is now used because it can be used for all types of compounds?
molar mass
atoms are too tiny to measure on an ordinary balance, so chemists came up with a more practical application for weighing them than grams... what do they use?
mole
what four units have been used in the past to refer to the mass of 1 mole of a compound?
molecular weight, molecular mass, formula weight, and formula mass
molar mass
the mass of one mole of a pure substance (how many grams of an element are in one mole of the same substance - g/mol)
mole
the unit for counting atoms (it's the way we count out an amount of atoms and mass them, since it's like, impossible to just give somebody 10 atoms or something)
through what are grams and mols related?
through the particular element/compound's molar mass
how many decimal places are we rounding each molar mass when calculating grams to mol or mol to grams?
two decimal places
how many moles of sodium hydroxide are there in 1.00 kg of NaOH?
well, first, the molar mass equals 40.00 g/mol 1.00 kg NaOH/1 x 1,000 g NaOH/1 kg NaOH x 1 mol NaOH/40.00 g NaOH = 25.0 mol NaOH
what is the mass of 5.00 moles of water?
well, first, the molar mass is 18.02 g/mol 5.00 mol H2O/1 x 18.02 g H2O/1 mol H2O = 90.1 g H2O
where is the molar mass located on the periodic table?
well, the molar mass is actually the average atomic mass of all the element's isotopes (they're the same thing), so, on our periodic table at least, it's in the bottom right-hand corner)
if given a coefficient of a compound, which elements does it apply and get distributed to? if given a subscript after a set of parentheses, which elements does it apply and get distributed to?
all of them in the entire compound; only the elements in the parentheses
what is one mole known as?
avogadro's number
if the formula of a compound is known, how can we determine its molar mass?
by adding the molar masses of all the atoms in the formula