WKST #4
Moles to number of particles
Name
Date
Blk
1 mole of a substance contains 6.02 x 1023 representative units of the substance
1 mole of an element = 6.02 x 1023 atoms of the element
Ex.: How many copper atoms are in 2.0 moles of copper?
2.0 moles Cu
x
6.02 x 1023 atoms Cu = 1.2 x 1024 atoms Cu
1 mole Cu
1 mole of a molecular compound = 6.02 x 102 3 molecules of the compound
Ex.: How many molecules of H2O are there in 0.5 mole H2O?
0.5 mole H2O x
H2O
6.02 x 1023 molecules H2O = 3.01 x 1023 molecules
1 mole H2O
1 mole of an ionic compound = 6.02 x 1023 formula units of the compound
Ex.: How many formula units of NaCl are there in 3.5 moles NaCl?
3.5 moles NaCl x
NaCl
6.02 x 1023 formula units NaCl = 2.1 x 1024 formula units
1 mole NaCl
1 mole of ions = 6.02 x 102 3 ions
Ex.: How many magnesium ions are there in 3.9 mole Mg2+ ?
3.9 mole Mg2+ x
6.02 x 1023 Mg2+ = 2.3 x 1024 Mg2+
1 mole Mg2+
1
Do ONLY the ASSIGNED calculations.
Do all work on separate paper and attach to this sheet. Show all work as usual.
NO work = NO credit
Calculate the number of atoms, ions, molecules, or formula units in each of the following
quantities. Not all representative particles have been given. You must identify the
representative particles not given.
1)
2)
3)
4)
5)
20.0 moles calcium metal
68.0 moles H2S
160.0 moles Br2
1.3 x 10 - 4 mole O2
5.6 x 103 moles P -3
6) 3.34 moles NaCl formula units
7) 0.125 mole Fe3+ ions
8) 293.0 moles O
9) 5.8 moles sulfur atoms
10) 8.30 x 10 -2 moles H2O molecules
Calculate the number of moles of each representative particle in each of the following
quantities. Not all representative particles have been given. You must identify the
representative particles not given.
11)
12)
13)
14)
15)
2
5.02 x 1015 Mg2+ ions
4.9 x 1021 molecules H2S
1.55 x 1026 formula units NaCl
3.79 x 1020 atoms S
3.765 x 1022 H2O
16)
17)
18)
19)
20)
5.00 x 1024 Zn2+
6.4 x 1019 CO
2.113 x 1036 Pb2+
7.09 x 1025 K
1.2 x 1022 BaCO3