Stoichiometry Stoichiometry: Calculations with Chemical Formulas and Equations.
Stoichiometry : Mathematics of chemical formulas and equations
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Transcript of Stoichiometry : Mathematics of chemical formulas and equations
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Stoichiometry: Mathematics of chemical formulas and equations
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MOLEMOLEMOLEMOLEA mole is just a number
pair = 2trio = 3quartet = 4dozen = 12baker’s dozen = 13gross = 144
mole = (mol) 602000000000000000000000
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THE MOLETHE MOLE 1 dozen cookies = 12 cookies 1 mole of cookies = 6.02 X 1023 cookies
1 dozen cars = 12 cars 1 mole of cars = 6.02 X 1023 cars
1 dozen Al atoms = 12 Al atoms 1 mole of Al atoms = 6.02 X 1023 atoms
Note that the NUMBER is always the same, but the MASS is very different!
Mole is abbreviated mol (gee, that’s a lot quicker to write, huh?)
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1 mole is the amount of substance that contains as many particles (atoms or molecules) as there are in 12.0 g of C-12.
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โมล (Mole,Mol) คื�อ หน่วยที่��บอกปริ�มาณอน่�ภาคืของสาริ ซึ่��งเป�น่หน่วยใหญ่ที่��ใช้#ที่��ใช้#แที่น่อน่�ภาคืจำ&าน่วน่มาก
อน่�ภาคื อะตอม
โมเลก�ล
ไอออน่
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AMADEO AVOGADRO(1776 – 1856)
1 mole = 602213673600000000000000or 6.022 x 1023
thousandsmillionsbillionstrillions
quadrillions?
There is Avogadro's number of particles in a mole of any substance.
Particles in a MoleParticles in a Mole
Amedeo Avogadro (1766-1856) never knew his own number;
it was named in his honor by a French scientist in 1909.
its value was first estimated by Josef Loschmidt, an Austrian
chemistry teacher, in 1895.
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A MOLE of any substance contains as many elementary units (atoms and molecules) as the number of atoms in 12 g of the isotope of carbon-12.
This number is called AVOGADRO’s number NA = 6.02 x 1023 particles/mol
The mass of one mole of a substance is called MOLAR MASS symbolized by MM
Units of MM are g/mol Examples
H2 hydrogen 2.02 g/molHe helium 4.0 g/mol N2 nitrogen 28.0 g/mol
O2 oxygen 32.0 g/mol
CO2 carbon dioxide 44.0 g/mol
AVOGADRO,S NUMBER
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MOLE
1. โมลก*บจำ&าน่วน่อน่�ภาคื
C-12 1 อะตอม ม�มวล 12 x 1.66 x 10-24 g
C-12 มวล 12 x 1.66 x 10-24 g ม�จำ&าน่วน่อะตอม = 1 atom
C-12 มวล 12 กรั�ม ม�จำ�นวนอะตอม = C-12 1 atom C-12 12 g
C-12 12 x 1.66 x 10-24 g
= 6.022137 x 1023 atom1 mole = 6.02 x 1023 อน่�ภาคื
Avogadro,s number
โมล หมายถึ�ง ปริ�มาณสาริที่��ม�จำ&าน่วน่อน่�ภาคืเที่าก*บจำ&าน่วน่อะตอมของคืาริ,บอน่-12 ที่��ม�มวล 12 กริ*ม
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AVOGADRO’S NUMBER
6.02 X 6.02 X 10102323
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MOLE
•ถึ#าอน่�ภาคืคื�ออะตอม เริ�ยกวา โมลอะตอม เช้น่ ส*งกะส� (Zn) 1 โมลอะตอมม�จำ&าน่วน่อะตอมเที่าก*บ 6 .0 2 x
1023
อะตอม• ถึ#าอน่�ภาคืคื�อโมเลก�ล เริ�ยกวา โมลโมเลก�ล เช้น่ ก-าซึ่ไฮโดริเจำน่ (H2) 1 โมลโมเลก�ลม�จำ&าน่วน่โมเลก�ลเที่าก*บ 602. x 10
23 โมเลก�ล
• ถึ#าอน่�ภาคืคื�อไอออน่ เริ�ยกวา โมลไอออน่ เช้น่ แคืลเซึ่�ยมไอออน่ (Ca2+) 1 โมลไอออน่ม�จำ&าน่วน่ไอออน่เที่าก*บ 602.x 1023 ไอออน่
•ถึ#าอน่�ภาคืคื�ออ�เล0กตริอน่ เริ�ยกวา โมลอ�เล0กตริอน่ 1 โมลอ�เล0กตริอน่ หมายถึ�ง จำ&าน่วน่อ�เล0กตริอน่เที่าก*บ 6.
02 x 10 23 อ�เล0กตริอน่
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= 6.02 x 1023 C atoms
= 6.02 x 1023 H2O molecules
= 6.02 x 1023 NaCl “molecules”(technically, ionics are compounds not
molecules so they are called formula units)
6.02 x 1023 Na+ ions and
6.02 x 1023 Cl– ions
A MOLE OF PARTICLESA MOLE OF PARTICLES CONTAINS 6.02 X 1023
PARTICLES 1 mole C
1 mole H2O
1 mole NaCl
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6.02 x 1023 particles
1 mole
or
1 mole
6.02 x 1023 particles
Note that a particle could be an atom OR a molecule!
AVOGADRO’S NUMBER AS AVOGADRO’S NUMBER AS CONVERSION FACTORCONVERSION FACTOR
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1. Number of atoms in 0.500 mole of Ala) 500 Al atoms
b) 6.02 x 1023 Al atomsc) 3.01 x 1023 Al atoms
2.Number of moles of S in 1.8 x 1024 S atomsa) 1.0 mole S atomsb) 3.0 mole S atomsc) 1.1 x 1048 mole S atoms
LEARNING CHECKLEARNING CHECK
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3. จำงหาจำ&าน่วน่โมลของสาริตอไปน่�11 .ฮ�เล�ยม 1204. x 1022 atom
2. แก-สแอมโมเน่�ย 301. x 1025 molecule
3. ส*งกะส� 3612 x 1020 atom
4. แมกน่�เซึ่�ยม 1 atom
5. โซึ่เด�ยมไอออน่ 20 ion
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If you had a mole of H2O could you swim in it?
NO!Water molecules are so small
that a mole of H2O = 18 ml
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HOW SMALL ARE ATOMS?There are more atoms in one gram of salt than grains of sand on all the beaches of all the oceans in all the world.
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GRAM ATOMIC MASS
mass in grams of 1 mole of atoms of an element
In other words…… 1 mol C atoms = 6.02 x 10 23 C
atoms = 12g C
of thein
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PRACTICE
REMEMBER . . .1 MOLE = 6.02X1023 ATOMS OR MOLECULES = ______ G FROM
THE PERIODIC TABLE
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MOLE
2 . จำ&าน่วน่โมลก*บมวลของสาริ
• ธ�ต�ใดๆ ที่��ม�ปรั�ม�ณ 6.02 x 1023 atom หรั�อ 1 โมล จำะม�มวลเป�นกรั�มเที่��ก�บมวลอะตอมของธ�ต�น�#น• ส�รัใดๆ ที่��ม�ปรั�ม�ณ 6.02 x 1023 molecule หรั�อ 1 โมล จำะม�มวลเป�นกรั�มเที่��ก�บมวลโมเลก�ลของส�รัน�#น•ไอออนใดๆ ที่��ม�ปรั�ม�ณ 6.02 x 1023 ion หรั�อ 1 โมล จำะม�มวลเป�นกรั�มเที่��ก�บมวลอะตอมของธ�ต�น�#น
คืาริ,บอน่-12 ปริ�มาณ 1 โมล ม�มวล 12 กริ*ม
คืามวลน่�1เริ�ยกวา มวลตอโมล
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Atomic Mass (g)
1 mole
or
1 mole
Atomic Mass (g)
CONVERSION FACTORCONVERSION FACTOR
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Molecular Mass (g)
1 mole
or
1 mole
Molecular Mass (g)
CONVERSION FACTORCONVERSION FACTOR
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1. จำงหาจำ&าน่วน่โมลของสาริตอไปน่�11 .น่&1า 036. g
2 .โพแที่สเซึ่�ยมไอโอไดด, 3806. g
3 .อะล3ม�เน่�ยม 270 g
4 .กล3โคืส 12 g
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2. จำงคื&าน่วณหามวลของสาริตอไปน่�1• ฮ�เล�ยม 1204. x 1022 atom
• แก-สแอมโมเน่�ย 301. x 1025 molecule
• ส*งกะส� 3612 x 1020 atom
• แมกน่�เซึ่�ยม 1 atom
• โซึ่เด�ยมไอออน่ 20 ion
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STOICHIOMETRY OF CHEMICAL FORMULAS
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GRAM FORMULA MASS GRAM MOLECULAR MASS
MOLAR MASS
mass in grams of 1 mole of a substance
In other words . . . Add it all up!
1 mole of NaCl = 58g = 6.02x1023 particles of NaCl
1 mole of H2O = 18g = 6.02x1023 molecules of H20
of thein
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NOW…..
Use the gram formula mass and the gram atomic mass to determine
how many moles or atoms of an element are found in some mass of a substance
how much mass that element contributes to the mass of the entire substance
Use factor label & follow the units!
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STOICHIOMETRY OF CHEMICAL FORMULAS
If you have 1 molecule of (NH4)2SO4How many atoms of N are there?How many atoms of H?
SO….. If you have 1 mole of of (NH4)2SO4
How many moles of N are there?How many moles of H?
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Gases ONLY@STP
MOLAR VOLUME
1 mole of any gasO2 (g)
NH3 (g)
He (g)
contains 6.02 x 1023 molecules andoccupies a volume of 22.4L
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STP
standard temperature &
pressure
0oC or 273K
101.3kPa or 1 atm
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REMEMBER . . . Gases also have mass
1 mole of O2(g) = 32g
1 mole of NH3(g) = 17g
we can calculate
Density!
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D = M/VA sample of oxygen contains 3 moles of particles at STP what is its density?
2 stepsConvert moles to mass AND volumeCalculate density
If mass or volume is given, use it and convert the other……. THEN calculate D!
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Remember . . .
1 mole = 6.02x1023 atoms or molecules =
gfm = 22.4L (g)
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MOLE
Ex. จำงคื&าน่วณหาจำ&าน่วน่โมลของคืาริ,บอน่ไดออกไซึ่ด, ปริ�มาตริ 56. dm3 ที่�� STP
3. จำ&าน่วน่โมลก*บปริ�มาตริของแก-สก&าหน่ดให# อ�ณหภ3ม� 0 องศาเซึ่ลเซึ่�ยส และคืวามด*น่ 1 บริริยากาศ เป�น่ภาวะมาตริฐาน่ (Standard Temperature and Pressure) และเริ�ยกยอวา STP
แก-สใดๆ 1 โมล ม�ปริ�มาตริ 224. ล3กบาศก,เดซึ่�เมตริ ( dm3 ) ที่�� STP หริ�อปริ�มาตริตอโมลของแก-สใด ๆ เที่าก*บ 2
24 dm3 หริ�อ 224 ล�ตริ ที่�� STP
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224. dm3 gas
1 mole
or
1 mole
224. dm3 gas
CONVERSION FACTORCONVERSION FACTOR
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1 mole
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Mole
ปริ�มาตริของแก-ส (dm3) ที่�� STP
มวล (g)
จำ&าน่วน่อะตอมหริ�อโมเลก�ล
ปริ�มาตริ 22.4 dm3
จำ&าน่วน่อน่�ภาคื 6.02 1023 อน่�ภาคื
มวลอะตอม
หริ�อมวลโมเลก�ล
คืวามส*มพ*น่ธ์,ริะหวางจำ&าน่วน่โมล อน่�ภาคื มวลและปริ�มาตริของแก-ส
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1 MOLE OF PARTICLES
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= 6.02 x 1023 C atoms
= 6.02 x 1023 H2O molecules
= 6.02 x 1023 NaCl “molecules”(technically, ionics are compounds not
molecules so they are called formula units)
6.02 x 1023 Na+ ions and
6.02 x 1023 Cl– ions
A MOLE OF PARTICLESA MOLE OF PARTICLES CONTAINS 6.02 X 1023
PARTICLES 1 mole C
1 mole H2O
1 mole NaCl
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The Mass of 1 mole (in grams)
Equal to the numerical value of the average
atomic mass (get from periodic table)
1 mole of C atoms = 12.0 g
1 mole of Mg atoms = 24.3 g
1 mole of Cu atoms = 63.5 g
MOLAR MASSMOLAR MASS
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OTHER NAMES RELATED TO MOLAR OTHER NAMES RELATED TO MOLAR MASSMASS
Molecular Mass/Molecular Weight: If you have a single
molecule, mass is measured in amu’s instead of grams. But,
the molecular mass/weight is the same numerical value as 1
mole of molecules. Only the units are different. (This is the
beauty of Avogadro’s Number!)
Formula Mass/Formula Weight: Same goes for
compounds. But again, the numerical value is the same.
Only the units are different.
THE POINT: You may hear all of these terms which mean the SAME NUMBER… just different units
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Find the molar mass
(usually we round to the tenths place)
LEARNING CHECK!LEARNING CHECK!
A.1 mole of Br atomsB.1 mole of Sn atoms
= 79.9 g/mole
= 118.7 g/mole
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Mass in grams of 1 mole equal numerically to the sum of the atomic masses
1 mole of CaCl2 = 111.1 g/mol
1 mole Ca x 40.1 g/mol
+ 2 moles Cl x 35.5 g/mol = 111.1 g/mol CaCl2
1 mole of N2O4 = 92.0 g/mol
MOLAR MASS OF MOLECULES MOLAR MASS OF MOLECULES AND COMPOUNDSAND COMPOUNDS
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A. Molar Mass of K2O = ? Grams/mole
B. Molar Mass of antacid Al(OH)3 = ? Grams/mole
LEARNING CHECK!LEARNING CHECK!
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Prozac, C17H18F3NO, is a widely used antidepressant
that inhibits the uptake of serotonin by the brain. Find
its molar mass.
LEARNING CHECKLEARNING CHECK
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molar mass Grams Moles
CALCULATIONS WITH MOLAR CALCULATIONS WITH MOLAR MASSMASS
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Aluminum is often used for the structure of light-weight bicycle frames. How many grams of Al are in 3.00 moles of Al?
3.00 moles Al ? g Al
CONVERTING MOLES AND CONVERTING MOLES AND GRAMSGRAMS
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1. Molar mass of Al 1 mole Al = 27.0 g Al
2. Conversion factors for Al
27.0g Al or 1 mol Al
1 mol Al 27.0 g Al
3. Setup 3.00 moles Al x 27.0 g Al
1 mole Al
Answer = 81.0 g Al
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The artificial sweetener aspartame
(Nutra-Sweet) formula C14H18N2O5 is
used to sweeten diet foods, coffee and
soft drinks. How many moles of
aspartame are present in 225 g of
aspartame?
LEARNING CHECK!LEARNING CHECK!
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ATOMS/MOLECULES AND ATOMS/MOLECULES AND GRAMSGRAMS
Since 6.02 X 1023 particles = 1 mole AND
1 mole = molar mass (grams) You can convert atoms/molecules to moles
and then moles to grams! (Two step process)
You can’t go directly from atoms to grams!!!! You MUST go thru MOLES.
That’s like asking 2 dozen cookies weigh how many ounces if 1 cookie weighs 4 oz? You have to convert to dozen first!
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molar mass Avogadro’s number Grams Moles particles
Everything must go through Moles!!!
CALCULATIONSCALCULATIONS
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ATOMS/MOLECULES AND ATOMS/MOLECULES AND GRAMSGRAMS
How many atoms of Cu are present in 35.4 g of Cu?
35.4 g Cu 1 mol Cu 6.02 X 1023 atoms Cu 63.5 g Cu 1 mol Cu
= 3.4 X 1023 atoms Cu
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LEARNING CHECK!LEARNING CHECK!
How many atoms of K are present in 78.4 g of K?
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LEARNING CHECK!LEARNING CHECK!
What is the mass (in grams) of 1.20 X 1024 molecules of glucose (C6H12O6)?
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LEARNING CHECK!LEARNING CHECK!
How many atoms of O are present in 78.1 g of oxygen?
78.1 g O2 1 mol O2 6.02 X 1023 molecules O2 2 atoms O 32.0 g O2 1 mol O2 1 molecule O2
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What is the percent carbon in C5H8NO4 (the
glutamic acid used to make MSG
monosodium glutamate), a compound used
to flavor foods and tenderize meats?
a) 8.22 %C
b) 24.3 %C
c) 41.1 %C
PERCENT COMPOSITIONPERCENT COMPOSITION
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Ex ถึ#าม�แก-สคืาริ,บอน่ไดออกไซึ่ด, (CO2) หน่*ก 9.24 g จำงคื&าน่วณหาก. จำ&าน่วน่โมล CO2
ข. จำ&าน่วน่โมเลก�ล CO2
คื. จำ&าน่วน่โมลของแตละธ์าต�ใน่คืาริ,บอน่ไดออกไซึ่ด, จำ&าน่วน่น่�1ง. จำ&าน่วน่อะตอมของแตละธ์าต� ( C = 12.0 O = 16.0 )
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ว�ธ์�ที่&าa. น่&1าหน่*กโมเลก�ลของ CO2 = 12.0 + ( 2 x 16.0 ) = 44.0
จำ&าน่วน่โมลของ CO2 = 924. g CO2 1 mol CO2
440. g CO2
= 0.210 mol CO2
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ข. Molecule CO2 = 924. g CO2 1 mol CO2 6.02 x 1023 molecule CO2
440 g CO2 1 mol CO2 = 1.26 x 1023 molecule CO2
ค. Mole C = 924. g CO2 1 mol CO2 1 mol C
440. g CO2 1 mol CO2
= 0.210 mole C
Mole O = 924. g CO2 1 mol CO2 2 mol O
440. g CO2 1 mol CO2
= 0.420 mole O
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ง. Atom C = 924. g CO2 1 mol CO2 1 mol C 6.02 1023 atom C
440. g CO2 1 mol CO2 1 mol C
= 1.26 1023 atom C
Atom O = 924. g CO2 1 mol CO2 2 mol O 6.02 1023 atom O
440. g CO2 1 mol CO2 1 mol O = 2.53 1023 atom O
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Ex. จำงหาจำ&าน่วน่โมล จำ&าน่วน่โมเลก�ล และปริ�มาตริ ที่�� STP ของสาริตอไปน่�1ซึ่��งม�มวล 100. g
1 .แก-สโอโซึ่น่ (O3)
2 .แก-สคืลอริ�น่ (Cl2)
3 .แก-สแอมโมเน่�ย (NH3)
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Ex. เฉลย1. แก-สโอโซึ่น่ (O3)
= 0.208 mol , 1.25 1023 molecule, 4.67 dm3 ที่�� STP
2 .แก-สคืลอริ�น่ (Cl2)
= 0.141 mol , 8.48 1022 molecule, 3.15 dm3 ที่�� STP
3. แก-สแอมโมเน่�ย (NH3)
= 0.587 mol , 3.53 1023 molecule, 13.2 dm3 ที่�� STP
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Concept of mole
1. What is the mass of 1.00 mol of each of the following elements?
a. Sodium……………………. b. Sulfur………………………. c. Chlorine……………………
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Concept of mole
2. How many moles of sodium atoms in 1.56 x 1021 atoms of sodium?
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Concept of mole
3. What is the total number of
atoms in 0.260 mol of glucose,
C6H12O6?
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Concept of mole
4. Determine the mass i n grams of each of the
following: a. 1 .3 5 mol Fe
b. 2 4 .5 mol O c. 0.876 mol Ca
125d. . mol Ca3
(PO4
)2
e. 0 .6 2 5 mol Fe(NO
3)3
f. 0.600 mol C4
H10
g. 1.45 mol (NH4
)2
CO3
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Concept of mole
5. Calculate the number of moles of each compound:
a. 21.5 g CaCO3
b. 1.56 g NH3
c. 16.8 g Sr(NO3)2
d. 6.98 g Na2CrO4
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