Chapter 10 “Chemical Quantities”
-
Upload
alden-gallagher -
Category
Documents
-
view
26 -
download
3
description
Transcript of Chapter 10 “Chemical Quantities”
![Page 1: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/1.jpg)
Chapter 10Chapter 10“Chemical Quantities”“Chemical Quantities”
You will need a calculator for this
chapter!
![Page 2: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/2.jpg)
Section 10.1 p. 287Section 10.1 p. 287The Mole: A Measurement The Mole: A Measurement
of Matterof Matter
![Page 3: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/3.jpg)
How do we measure items?How do we measure items?You can measure mass, volume,or count pieces
We measure mass in gramsWe measure volume in litersWe count pieces in MOLES
![Page 4: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/4.jpg)
Other Ways to Measure Other Ways to Measure AmountAmount
Pair: 1 pair of socks = 2 socks Dozen: 1 dozen donuts = 12 donuts Gross: 1 gross of pencils = 144
pencils (12 dozen) Ream: 1 ream of paper = 500
sheets of paperGuided Practice Problem p. 289
![Page 5: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/5.jpg)
Practice Problem #2 Practice Problem #2 pg. 289pg. 289
• Assume 2.0 kg of apples is 1 dozen and that each apple has 8 seeds. How many apple seeds are in 14 kg of apples? (work INDEPENDENTLY to solve)
![Page 6: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/6.jpg)
What is the mole?
Not this kind of mole!
![Page 7: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/7.jpg)
Moles (abbreviated Moles (abbreviated molmol))Derived from German word molekül (molecule)
SI measurement of an amount 1 mole = 6.02 x 1023 of representative particles, or…..
# of carbon atoms in exactly 12 g of Carbon-12 isotope
Called Avogadro’s numberAvogadro’s number
![Page 8: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/8.jpg)
What are Representative Particles?What are Representative Particles?
(Table 10.1 p. 290)(Table 10.1 p. 290) The smallest pieces of a
substance:1) molecular cmpd - molecule2) ionic cmpd - formula unit (made
of ions)3) element: is the
• Remember the 7 diatomic elements? (made of molecules) BrINClHOFH2
N2 O2 F2Cl2
I2Br2
atoatomm
Guided Practice Problem #3 p. 291
![Page 9: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/9.jpg)
Mole Video 3:49
![Page 10: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/10.jpg)
Quick QuizQuick Quiz• How big is a mole?• If everyone in the world got a mole of
pennies, how much $ would every person have?
• If you stacked a mole of paper how many times would it go from the Earth to the moon?
• How long would it take for every person in the world to eat through a mole of marshmellows?
6.02 x 6.02 x 10102323
1 trillion bucks1 trillion bucks$1,000,000,000,000$1,000,000,000,000
80 billion 80 billion timestimes80,000,000,00080,000,000,000
40,000,000 years w/o 40,000,000 years w/o a bathroom break!a bathroom break!
![Page 11: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/11.jpg)
Consider these questions:Consider these questions:• How many oxygen atoms in
the following?CaCO3
Al2(SO4)3
• How many ions in the following?CaCl2NaOHAl2(SO4)3
3 atoms of oxygen
12 (3 x 4) atoms of oxygen
3 total ions (1 Ca2+ ion and 2 Cl1- ions)
2 total ions (1 Na1+ ion and 1 OH1- ion)
5 total ions (2 Al3+ + 3 SO42- ions)
![Page 12: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/12.jpg)
Practice problemsPractice problems
![Page 13: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/13.jpg)
The Mass of a Mole of an The Mass of a Mole of an ElementElement
Atomic mass of element (mass of 1 atom) expressed in amu- atomic masses - relative masses based on mass of C-12 (12.0 amu)
- 1 amu is 1/12 mass of C-12 atom
![Page 14: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/14.jpg)
Molar Mass…. Molar Mass…. = mass of 1 mol of element in in
gramsgrams (periodic table) 12.01 grams C has same #
particles as 1.01 g H & 55.85 g Fe 12.01 g C = 1 mol C 1.01 g H = 1 mol H 55.85 g Fe = 1 mol Fe
All All contain contain 6.02 x 6.02 x 10102323 atomsatoms
![Page 15: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/15.jpg)
Molar Mass Practice Molar Mass Practice ProblemsProblems
![Page 16: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/16.jpg)
What about compounds?What about compounds? 1 mol of H2O molecules has 2
mol of H atoms & 1 mol of O atoms (think of a compound as a molar ratio)
To find mass of 1 mol of a cmpd: odetermine # moles of elements presentoMultiply # times their mass (from periodic table)oadd up for total mass
![Page 17: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/17.jpg)
Calculating Molar MassCalculating Molar Mass
Calculate molar mass of magnesium carbonate, MgCO3.
24.3 g + 12.0 g + 3 x (16.00 g) = 84.3 g
So, 84.3 g = molar mass for MgCO3
![Page 18: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/18.jpg)
Section 10.2 Section 10.2 p. 297p. 297
Mole-Mass and Mole-Mole-Mass and Mole-Volume RelationshipsVolume Relationships
![Page 19: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/19.jpg)
Molar MassMolar MassMolar mass - generic term for
mass of 1 mol of any substance (expressed in grams/mol)
Same as: 1) Gram Molecular Mass (for molecules)
2) Gram Formula Mass (ionic
compounds) 3) Gram Atomic Mass (for elements)
o molar mass is more broad term than these other specific masses
![Page 20: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/20.jpg)
ExamplesExamples Calculate the molar mass of:Na2S
N2O4
C Ca(NO3)2
C6H12O6
(NH4)3PO4
= 78.05 g/mol
= 92.02 g/mol
= 12.01 g/mol
= 164.10 g/mol
= 180.12 g/mol
= 149.12 g/mol
![Page 21: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/21.jpg)
Molar Mass is…Molar Mass is…# of g in 1 mol of atoms, formula units, or molecules
Make conversion factors from these- To change btwn g of cmpd and mol of cmpd
![Page 22: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/22.jpg)
Using the Mole RoadmapUsing the Mole RoadmapHow many moles is 5.69 g of NaOH?0.142 mol NaOH
![Page 23: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/23.jpg)
The Mole-Volume RelationshipThe Mole-Volume Relationshipgases
- hard to determine masshow many moles of gas?2 things affect gas V:
a) Temp & b) Pressurecompare all gases at = temp & pressure
![Page 24: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/24.jpg)
Standard Temperature and PressureStandard Temperature and Pressure 0ºC & 1 atm pressure
- abbreviated “STP” At STP, 1 mol of anyany gas has V of 22.4 L- Called molar volume
1 mol of any gas at STP = 22.4 L
![Page 25: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/25.jpg)
Practice ExamplesPractice Examples
![Page 26: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/26.jpg)
Mole DayCelebrated on October 23rd from 6:02 am until 6:02 pm(6:02 on 10-23)
![Page 27: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/27.jpg)
Density of a gasDensity of a gas D = m / V (density = mass/volume)- for gas units are: g / L
find density of a gas at STP if formula known
You need: 1) mass and 2) volume Assume 1 mol, so mass is molar mass (from periodic table)
At STP, V = 22.4 L
![Page 28: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/28.jpg)
Practice Examples Practice Examples (D=m/V)(D=m/V)
![Page 29: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/29.jpg)
Another way:Another way: If given densityIf given density, find molar mass
of gas Assume 1 mol at STP, so V = 22.4 L
modify: D = m/V to show: “m” will be mass of 1 mol, given
22.4 L What is molar mass of a gas with
density of 1.964 g/L? How about a density of 2.86 g/L?
= 44.0 g/mol
64.0 g/mol
m = D x V
![Page 30: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/30.jpg)
SummarySummary• all equal:all equal:
a) 1 moleb) molar mass (in grams/mol)c) 6.02 x 1023 representative particles (atoms, molecules, or formula units)
d) 22.4 L of gas at STPmake conversion factors from these 4 values (p.303)
![Page 31: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/31.jpg)
Notice all conversions Notice all conversions must go through the must go through the
MOLE!MOLE!Copy this conversion Copy this conversion map into your notes!map into your notes!
![Page 32: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/32.jpg)
Section 10.3Section 10.3p. 305p. 305
Percent Composition Percent Composition and Chemical and Chemical
FormulasFormulas
![Page 33: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/33.jpg)
All percent problems: part whole
1)1) Find mass of each element,Find mass of each element,
2)2) Divide by total mass of cmpd; & x Divide by total mass of cmpd; & x 100100
x 100 % = percent
%mass of element = mass of element
x 100% mass of cmpd
![Page 34: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/34.jpg)
% composition from mass% composition from mass Calculate the percent
composition of a compound that is made of 29.0 grams of Ag with 4.30 grams of S.
29.0 g Ag33.3 g total
X 100 = 87.1 % Ag
4.30 g S33.3 g total
X 100 = 12.9 % S
Total = 100 %
![Page 35: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/35.jpg)
% comp from the chemical formula% comp from the chemical formula If we know formula, assume
you have 1 mole, Subscripts used to calculate
mass of each element in 1 mole of cmpd
sum of masses is molar mass
![Page 36: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/36.jpg)
% Composition Examples% Composition Examples
![Page 37: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/37.jpg)
% composition as % composition as conversion factorconversion factor
We can also use % as conversion factor conversion factor to calculate # grams of element in cmpd
Calculate % C in Calculate % C in C3H8
What is mass of C in 82.0 g sample of propane (C3H8)
67.1 g C
![Page 38: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/38.jpg)
% Composition% Composition4:15
![Page 39: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/39.jpg)
What is an Empirical Formula?What is an Empirical Formula?• Like ingredients for recipe –
double recipe, you double each ingredient, but ratioratio of ingredients stays same
• Empirical formula: lowest whole number ratio of atoms in cmpd
![Page 40: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/40.jpg)
Calculating EmpiricalCalculating EmpiricalFind lowest whole number ratio
C6H12O6
CH4NA formula is not just ratio of
atomsatoms, it is also ratio of moles1 moleculemolecule of CO2 = 1 atom of C atom of C and 2 atoms of O 2 atoms of O
1 mol of CO2 = 1 mol C and 2 mol O
= CH2O
= this is already the lowest ratio.
![Page 41: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/41.jpg)
Calculating EmpiricalCalculating Empirical get a ratio from % composition1)Assume you have a 100 g
sample- the percentagepercentage become gramsgrams (75.1%75.1% = 75.1 75.1
gramsgrams)
2) Convert gramsgrams to molesmoles. 3) Find lowest whole number ratio
by dividing each # of molesmoles by smallest value
![Page 42: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/42.jpg)
ExampleExampleCalculate empirical formula of cmpd composed of 38.67 % C, 16.22 % H, and 45.11 %N.
Assume 100 g sample, so 38.67 g C x 1mol C = 3.22 mole C
12.0 g C 16.22 g H x 1mol H = 16.22 mole
H 1.0 g H 45.11 g N x 1mol N = 3.22 mole
N 14.0 g N
Now divide each value by the smallest value
CH5N
![Page 43: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/43.jpg)
ExampleExample The ratio is 3.22 mol C = 1 mol C
3.22 mol N 1 mol N
The ratio is 16.22 mol H = 5 mol H 3.22 mol N 1 mol
N
= C1H5N1 which is = CH5N
![Page 44: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/44.jpg)
Practice Problem 36 p. 310Practice Problem 36 p. 310
![Page 45: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/45.jpg)
What is a Molecular Formula?What is a Molecular Formula?• Molecular formula: true # of atoms of
each element in formula of cmpd
• molecular cmpds only• Example: molecular formula for
benzene is C6H6 (note that everything is divisible by 6) • Therefore, empirical formula =
CH (the lowest whole number ratio)
![Page 46: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/46.jpg)
FormulasFormulas (continued)(continued)
ionic compoundsionic compounds ALWAYS empirical (cannot be reduced).
Examples:
NaCl MgCl2 Al2(SO4)3 K2CO3
![Page 47: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/47.jpg)
FormulasFormulas (continued)(continued)
Formulas for molecular compoundsmolecular compounds
MIGHT be empirical (lowest whole number ratio).
Molecular:
H2O
C6H12O6 C12H22O11
Empirical:
H2O
CH2O C12H22O11
(Correct formula)
(Lowest whole number ratio)
![Page 48: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/48.jpg)
Empirical to molecularEmpirical to molecularSince empirical formula is lowest ratio, the actual molecule weighs more
Molar mass
Empirical formula masswhole # to increase each coefficient in empirical formula
=
![Page 49: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/49.jpg)
Empirical to molecular Empirical to molecular practice problempractice problem
![Page 50: Chapter 10 “Chemical Quantities”](https://reader036.fdocuments.net/reader036/viewer/2022062408/5681307e550346895d9659a1/html5/thumbnails/50.jpg)
Empirical and Empirical and Molecular FormulasMolecular Formulas
3:29