Transcript 06-Molar Conversions_ etc

Molar
Conversions
Moles
The standard unit of
measure for the
amount of a
substance in numbers
Dozen
= 12 of
anything
Moles
= the amount of a
substance that
would = its mass in
g from the PT
Moles
23
10
= 6.022 x
of anything
Molar Conversions
• Mass to moles
• Volume of a gas to moles
• Particles to moles
• Volume of a solution to
moles
Converting to
Moles
From Mass
• Use atomic masses
from the periodic table
• NaCl = 58.5 g/mole
* 6.022 x 1023 amu = 1 g
From Gas Volume
•At STP multiply volume
by (1 mole/22.4 L)
•At non-STP use
PV = nRT
Particles to Moles
Multiply # particles by this
conversion factor:
1 mole atoms OR molecules
6.02 x 1023 atoms OR molecules
* pay attention to the question!
From Sol’n Volume
• Multiply molarity (M)
by volume (in L)
•n = M x V
* M = moles/L
Convert 7.0 g
of silicon to
moles of Si
• 7.0 g Si
1 mole Si = 2.5 x 10-1 mol Si
28.0855 g Si
Convert 250 g of
CaCO3 to:
• moles of CaCO3
• how many moles
of O?
• 250 g CaCO3 1 mol CaCO3
100.0872 g CaCO3
• 250 g CaCO3 1 mol CaCO3
100.0872 g CaCO3
= 2.5 mol
CaCO3
3 mol O =
1 mol CaCO3
7.5 mol O
Convert 3.0
moles of helium
to grams of He
•
3.0 mol He 4.0026 g He = 12 g He
1 mol He
Convert 5.6 L of
oxygen gas at
STP to moles
Oxygen atoms
• 5.6 L O2
1 mole O2
22.4 L
2 mol O = 0.50 mol O
1 mol O2
Convert 0.500
moles of helium
to volume at
STP
• 0.500 mol He 22.4 L He = 11.2 L He
1 mol He
Convert:
24
2.0 x 10 atoms
He to moles
• 2.0 x 1024 atoms He
1 mol He
6.02 x 10 23 atoms He
= 3.3 mol He
Convert 3.0
moles of glucose
to molecules
3.0 mol C6H12O6 6.022 x 1023 molecules C6H12O6
1 mol C6H12O6
= 1.8 x 1024 molecules C6H12O6
Convert 250 mL
of 0.10 M HCl
to moles
• 0.10 M HCL = 0.10 mol HCL
1L
• 250 mL
1L
103 mL
0.10 mol HCL
1 L H2O
= 2.5 x 10-2 mol HCL
Determine the
volume required
to make 60.0 g
NaOH into a 0.75
M solution
60 g NaOH
1 mol NaOH = 1.500 mol NaOH
39.9971 g NaOH
1.500 mol NaOH = 0.75 M NaOH
X L H2O
X = 2 L H2O
Convert 6.8 g
NH3 to volume
at STP
• 6.8 g NH3
1 mole NH3
22.4 L NH3
17.031 g NH3 1 mole NH3
= 8.9 L NH3
25
10
Convert 3.0 x
molecules of CO2
to mass in kg
• 3.0 x 1025 molecules CO2
1 mol CO2
6.022 x 1023 molecules CO2
44.095 g CO2
1 mole CO2
1kg
103 g
= 2.2 kg
Calculate the
number of oxygen
atoms in 32 mg of
Fe2O3
Calculate the
number of atoms
in 16 ng of
Fe2(SO4)3
Calculate the mass
of solute required to
make 40.0 mL of
0.25 M Pb(NO3)2