chapter 11 notes, part i what is a mole? one step problems
TRANSCRIPT
Chapter 11 Notes, Part IWhat is a mole?
One Step Problems
What is a mole?
• A furry, burrowing woodland creature, revered by many and adored by all?
Maybe!• But not really in chemistry!
A Mole...
• is a unit of measurement that tells how many particles of something you have!
• much like a dozen (12), a gross (144) or a ream (500) is just a unit that groups smaller numbers into big ones...but its a big one; a REALLY big one!
1 mole = 6.02 x 1023 particles!
(that’s a lot of flowers!)
What are particles?
• Particles could be anything, but because of the size of the number, we usually mean
Atoms,
molecules, or
formula units.
Avogadro’s Number
• The number 6.02 x 1023 is called Avogadro’s number.
• This is due to Amadeo Avagadro’s research leading to the discovery, not the discovery of the number itself.
It is a little known fact that Avogadro was voted It is a little known fact that Avogadro was voted his class’s most likely to have a scientific his class’s most likely to have a scientific
discovery and most likely to look really creepy.discovery and most likely to look really creepy.
Obj. 1…Formula vs. Molecular Obj. 1…Formula vs. Molecular MassMass
• Formula mass = total mass of ionic compoundsFormula mass = total mass of ionic compounds
- starts with a metal- starts with a metal
• Molecular mass = total mass of molecular compoundsMolecular mass = total mass of molecular compounds
- starts with a non-metal- starts with a non-metal
• To calculate…To calculate…
- find mass of each element on P.T. (whole #s)- find mass of each element on P.T. (whole #s)
- multiply mass by subscript and/or coefficient- multiply mass by subscript and/or coefficient
- add all masses together for total mass- add all masses together for total mass
Obj. 1 cont…Obj. 1 cont…
• Practice…Practice…
AlAl22(SO(SO44))33
27 x 2 = 5427 x 2 = 54
32 x 3 = 9632 x 3 = 96
16 x 12 = 19216 x 12 = 192
54 + 96 + 192 = 54 + 96 + 192 = 342 amu342 amu
formula massformula mass
SS33FF66
32 x 3 = 9632 x 3 = 96 19 x 6 = 11419 x 6 = 114
96 + 114 = 96 + 114 = 210 amu210 amu
molecular massmolecular mass
• more practice…more practice…
Obj. 1 cont…Obj. 1 cont…
3CaC3CaC22OO44
40 x 3 = 12040 x 3 = 120
12 x 6 = 7212 x 6 = 72
16 x 12 = 19216 x 12 = 192
120 + 72 + 192 = 120 + 72 + 192 =
384 amu384 amu
OROR 40 x 1 = 4040 x 1 = 40
12 x 2 = 2412 x 2 = 24
16 x 4 = 6416 x 4 = 64
40 + 24 + 64 = 40 + 24 + 64 = 128 128 x 3 =x 3 =
384 amu384 amu
CuSOCuSO44 5H 5H22OO
two compounds chemically bonded together… two compounds chemically bonded together… NOTNOT multiply!!! multiply!!!
6464 3232 6464 1010 8080
64 + 32 + 64 + 10 + 80 = 64 + 32 + 64 + 10 + 80 = 250 amu250 amu
• recall that one precall that one p+ + / n/ n00 = 1.67 x 10 = 1.67 x 10-24-24 grams grams
• therefore…one mole of nucleons = 1 gramtherefore…one mole of nucleons = 1 gram
Obj. 2 cont…Obj. 2 cont…
** 1.67E ** 1.67E -24-24 x 6.02E23 = 1 x 6.02E23 = 1
• amu = g/moleamu = g/mole
• one mole = one mole =
~~ 6.02 x 10 6.02 x 102323 atoms, molecules or ions in a compound atoms, molecules or ions in a compound
~~ molar mass of compound / element molar mass of compound / element
molar massmolar massatomic massatomic mass
~~ 22.4 liters of any gas at 22.4 liters of any gas at STPSTP (standard temp. and pressure)(standard temp. and pressure)
00°C°C 760 mmHg760 mmHg101.3 kPa101.3 kPa
1 atm1 atm273K273K
Obj. 3-7…Mole ConversionsObj. 3-7…Mole Conversions
MoleMoleLitersLiters
# of atoms/ # of atoms/ moleculesmolecules
GramsGramsX by 22.4X by 22.4
by 22.4by 22.4
by molar mass by molar mass
X by molar mass X by molar mass
X by 6.02 x 10X by 6.02 x 102323 by 6.02 x 10by 6.02 x 102323
• use ‘mole map’ to solve mole conversions…use ‘mole map’ to solve mole conversions…** going ** going away away from moles = x from moles = x
** going ** going toward toward moles = moles = ÷÷
Obj. 3-7 cont…Obj. 3-7 cont…• Practice, practice, practice…Practice, practice, practice…
2.0 moles He = ____________ atoms He 2.0 moles He = ____________ atoms He
2.0 moles x 6.02E23 = 2.0 moles x 6.02E23 =
1.2 x 101.2 x 102424
2.0 moles H2.0 moles H22O = ____________ grams HO = ____________ grams H22O O
2.0 moles x 18 = 2.0 moles x 18 =
36 36
22 1616 = 18= 18
67.2 liters O67.2 liters O22 = ____________ moles O = ____________ moles O22
67.2 liters 67.2 liters ÷÷ 22.4 = 22.4 =
3.00 3.00
27 grams H27 grams H22O = ____________ moles HO = ____________ moles H22O O
22 1616 = 18= 18
27 grams 27 grams ÷÷ 18 = 18 =
1.5 1.5
Obj. 3-7 cont…Obj. 3-7 cont…• more practice…more practice…
3.61 x 103.61 x 102424 molecules NaCl = ____________ moles NaCl molecules NaCl = ____________ moles NaCl
3.61 x 103.61 x 102424 molecules molecules ÷÷ 6.02 x 10 6.02 x 102323 = =
6.00 6.00
5.0 moles CO5.0 moles CO22 = ____________ liters CO = ____________ liters CO22
5.0 moles 5.0 moles xx 22.4 = 22.4 =
110110
**** 3.61 x 103.61 x 102424 molecules CO molecules CO22 = ____________ grams CO = ____________ grams CO2 2 ** **
3.61 x 103.61 x 102424 molecules molecules ÷÷ 6.02 x 10 6.02 x 102323 = 6 moles x = 6 moles x
122 3232 = 44= 44
44 grams =44 grams =
264264
Practice Problem #1
• How many moles are in 2.57 x 10How many moles are in 2.57 x 102525 atoms He?atoms He?
Practice Problem #2
• How many molecules of CO2 are in 25.3 moles?
Practice Problem #3
• How many moles of O2 are in 29.3L of O2 gas?
Practice Problem #4
• If you have 3.6 moles of N2O (Nitrous oxide) how many liters would you have?
Practice Problem #5
• How many grams of iron are in 3.5 moles?
Practice Problem #6
• How many moles of Na2O are in 355.1g?