Chapter 10.1Chapter 10.1

The Mole: A Measurement of The Mole: A Measurement of MatterMatter

►Three ways of measuring things…Three ways of measuring things…count, mass, & volume.count, mass, & volume.

►Examples: soda—6 packExamples: soda—6 pack► soda—litersoda—liter► grapes--lbsgrapes--lbs

►Terms for specific counts…pair, dozen, Terms for specific counts…pair, dozen, etc.etc.

►1 dozen apples = 12 apples.1 dozen apples = 12 apples.►1 dozen apples = 2.0 kg apples.1 dozen apples = 2.0 kg apples.►1 dozen apples = 0.2 bushels apples.1 dozen apples = 0.2 bushels apples.►Ratios: 1 dozen apples/12 applesRatios: 1 dozen apples/12 apples►1 dozen apples/2.0 kg apples1 dozen apples/2.0 kg apples►1 dozen apples/0.2 bushels apples1 dozen apples/0.2 bushels apples

Problem…Problem…

►What is the mass of 90 apples if 1 What is the mass of 90 apples if 1 dozen apples = 2.0 kg?dozen apples = 2.0 kg?

►Analyze…known…Analyze…known…►# of apples = 90# of apples = 90►12 apples = 1 dozen12 apples = 1 dozen►1 dozen = 2.0 kg1 dozen = 2.0 kg►Unknown…mass of 90 apples = ?kgUnknown…mass of 90 apples = ?kg

CalculateCalculate

EvaluateEvaluate

►Does it make sense?Does it make sense?►Practice…What is the mass of 0.5 Practice…What is the mass of 0.5

bushels of apples?bushels of apples?

►Practice…assume 8 seeds per apple. Practice…assume 8 seeds per apple. How many seeds are in 14 kg of How many seeds are in 14 kg of apples?apples?

What is a Mole?What is a Mole?

►A specified number of particles. Used A specified number of particles. Used by chemists. by chemists. 6.02 x 106.02 x 102323 representative particles (Avagrado’s representative particles (Avagrado’s number).number).

►Representative particles can be atoms, Representative particles can be atoms, molecules, or formula units.molecules, or formula units.

►Ratio: 1 mole/6.02x10Ratio: 1 mole/6.02x102323 rep. particles rep. particles

Scientific basis of the moleScientific basis of the mole

►6.02x106.02x102323 is the number of atoms in 12 is the number of atoms in 12 grams of Carbon-12.grams of Carbon-12.

► If one mole of carbon-12 atoms were If one mole of carbon-12 atoms were weighed, it would weigh exactly 12 weighed, it would weigh exactly 12 grams.grams.

Atoms to molesAtoms to moles

►How many moles in 1.25x10How many moles in 1.25x102323 atoms atoms of magnesium?of magnesium?

►Known; # of atoms = 1.25x10Known; # of atoms = 1.25x102323

►1 mole = 6.02x101 mole = 6.02x102323 atoms Mg. atoms Mg.►Unknown; moles of magnesium.Unknown; moles of magnesium.►Calculate…Calculate…

Moles to # of particlesMoles to # of particles

►How many atoms in a mole? First How many atoms in a mole? First determine how many atoms in a determine how many atoms in a representative particle.representative particle.

►How many atoms in 2.12 moles of How many atoms in 2.12 moles of propane (Cpropane (C33HH88)?)?

►Known: # of moles of CKnown: # of moles of C33HH88 is 2.12. 1 is 2.12. 1 mole = 6.02x10mole = 6.02x102323 moleculesmolecules C C33HH88. 1 . 1 molecule Cmolecule C33HH88 = 11 atoms. = 11 atoms.

►Unknown: # of atoms.Unknown: # of atoms.

►Calculate…Calculate…

►Practice…Practice…►How many How many atomsatoms in 1.14 moles SO in 1.14 moles SO33??

►How many How many molesmoles in 4.65x10 in 4.65x102424 molecules NOmolecules NO22??

The Mass of a Mole of an The Mass of a Mole of an ElementElement

►Mass of atoms expressed in amu’s Mass of atoms expressed in amu’s (atomic mass units), which are relative (atomic mass units), which are relative units based on the isotope Carbon-12 units based on the isotope Carbon-12 (12.0 amu).(12.0 amu).

►C-12 is twelve times heavier than an C-12 is twelve times heavier than an average hydrogen atom with a mass of average hydrogen atom with a mass of 1.0 amu.1.0 amu.

►100 C-12 atoms are 12 times heavier 100 C-12 atoms are 12 times heavier than 100 hydrogen atoms.than 100 hydrogen atoms.

►AnyAny number of C-12 atoms are number of C-12 atoms are alwaysalways twelve times heavier than the same twelve times heavier than the same number of hydrogen atoms.number of hydrogen atoms.

►The mass ratio of 12 carbon atoms to 1 The mass ratio of 12 carbon atoms to 1 hydrogen atom is the same regardless hydrogen atom is the same regardless of the units used to express the mass.of the units used to express the mass.

►Therefore, 12.0 g of carbon atoms and Therefore, 12.0 g of carbon atoms and 1.0 g of hydrogen atoms 1.0 g of hydrogen atoms mustmust have have the same number of atoms. the same number of atoms.

Representative ParticleRepresentative Particle

► Smallest unit in a substanceSmallest unit in a substance► Can be different thingsCan be different things

1.1. One atom (metals, atomic substances)One atom (metals, atomic substances)

2.2. One molecule (molecular compounds)One molecule (molecular compounds)

3.3. One ion (charged atoms or molecules)One ion (charged atoms or molecules)

4.4. One formula unit (ionic compounds)One formula unit (ionic compounds)

Examples of Examples of Representative Representative particlesparticles

SubstanceSubstance RepresentativRepresentative particlee particle

FormulaFormula

Iron Iron atomatom FeFe

Atomic Atomic nitrogennitrogen

atomatom NN

Nitrogen gasNitrogen gas moleculemolecule NN22

waterwater moleculemolecule HH22OO

Calcium ionCalcium ion ionion CaCa2+2+

Calcium Calcium fluoridefluoride

Formula unitFormula unit CaFCaF22

glucoseglucose moleculemolecule CC66HH1212OO66

Measuring Chemical Measuring Chemical SubstancesSubstances

►Using Avogadro’s number: a specific Using Avogadro’s number: a specific number of number of representative particlesrepresentative particles

6.02 x 106.02 x 102323 RP/moleRP/mole►Referred to as Referred to as one mole (mol)one mole (mol)Example: One mol water containsExample: One mol water contains►6.02 x 106.02 x 102323 H H220 molecules0 moleculesExample: one mole nitrogen gas…Example: one mole nitrogen gas…

PracticePractice

Q: how many moles does 1.25 x 10Q: how many moles does 1.25 x 1023 23 atoms of Mg atoms of Mg represent?represent?

A: 1.25 x 10A: 1.25 x 1023 23 Mg atoms x (6.03 x 10Mg atoms x (6.03 x 1023 23 RP)/mole =RP)/mole =0.2 moles 0.2 moles Q: how many moles does 2.8 x 10Q: how many moles does 2.8 x 1024 24 atoms of silicon atoms of silicon

have?have?A: 2.8 x 10A: 2.8 x 1024 24 Si atoms/6.03 x 10Si atoms/6.03 x 1023 23 RP/mole =RP/mole =4.6 moles4.6 moles

Q:Q: How many propane (CQ:Q: How many propane (C33HH88) molecules are in 2.12 ) molecules are in 2.12 mol of Cmol of C33HH88 ? ?

A: 2.12 moles x (6.03 x 10A: 2.12 moles x (6.03 x 102323 ) ) RP/mole = 12.8 RP/mole = 12.8

Converting molecular Moles into Converting molecular Moles into Number of individual atomsNumber of individual atoms

Hint: when asked for # of atoms always Hint: when asked for # of atoms always dodo

Moles #molecules #atomsMoles #molecules #atoms

PracticePractice

Q: How many Q: How many atomsatoms are in 2.12 mol of C are in 2.12 mol of C33HH88 ? ?► First calculate how many moleculesFirst calculate how many moleculesA: 2.12 moles x (6.02 x 10A: 2.12 moles x (6.02 x 102323 RP)/mole= 12.76 x 10 RP)/mole= 12.76 x 102323

RP = 1.28 x 10RP = 1.28 x 102424 RP RP► Then calculate how many atomsThen calculate how many atoms

Each RP (CEach RP (C33HH88) has 11 atoms/RP) has 11 atoms/RPMultiply with 11: 1.28 x 10Multiply with 11: 1.28 x 102424 RP x 11 Atoms/Rp= RP x 11 Atoms/Rp=14.08 X 1014.08 X 102424 atoms atoms► Clean all results to single digit number!!!Clean all results to single digit number!!!14.08 X 1014.08 X 102424 → → Atoms = 1.4 x 10Atoms = 1.4 x 102525 atoms atoms

PracticePractice

You have 4.65 x 10You have 4.65 x 1024 24 molecules of NOmolecules of NO22??

Q: How many atoms?Q: How many atoms?

A: RP NOA: RP NO22 has three atoms/molecule has three atoms/molecule

3 atoms/molecule x 4.65 x 103 atoms/molecule x 4.65 x 1024 24

molecules molecules

The mass of one mole of a given The mass of one mole of a given elementelement

►Mass of an element is indicated in the Mass of an element is indicated in the periodic table as the mass number periodic table as the mass number

►Called Called amuamu = atomic mass unit = atomic mass unit►amu is the mass (in grams) of one amu is the mass (in grams) of one

mole of this elementmole of this element►Remember it is an average number of Remember it is an average number of

the different isotopes…it has decimals the different isotopes…it has decimals

Finding massFinding mass

►What is the What is the mass of one molemass of one mole O, P, O, P, K, S-33, K, S-33, 1414

66CC

►Atomic oxygen: 16.00 g/moleAtomic oxygen: 16.00 g/mole►Atomic phosphorus: 30.97 g/moleAtomic phosphorus: 30.97 g/mole►Atomic potassium: 39.10 g/moleAtomic potassium: 39.10 g/mole►Atomic S-33: 33.00 g/moleAtomic S-33: 33.00 g/mole►Atomic Atomic 1414

66C: 14.00 g/moleC: 14.00 g/mole

How many mole in a given How many mole in a given massmass

►How many moles of Carbon are found How many moles of Carbon are found in 52 g?in 52 g?

►52 g/12.01 g/mole C= 4.33 moles C52 g/12.01 g/mole C= 4.33 moles C

Practice calculating molar Practice calculating molar massesmasses

Q: How many moles of C-14 are found in 34 g?Q: How many moles of C-14 are found in 34 g?► 34 g x mole C-14/14g C-14 = 2.42 moles C-34 g x mole C-14/14g C-14 = 2.42 moles C-

1414Q: What mass does 6.02 x 10Q: What mass does 6.02 x 102323 atoms of atoms of

Hydrogen have?Hydrogen have?► Is one mole Is one mole → 1.01 g→ 1.01 gQ: What is the mass of 2.34 x 10Q: What is the mass of 2.34 x 102222 atoms of atoms of

phosphorus? First find how many molesphosphorus? First find how many moles2.34 x 102.34 x 102222 atoms x mole/6.02 x 10 atoms x mole/6.02 x 102323 atoms = atoms =

0.04 moles P0.04 moles P0.04 moles P x 30.97 g/mole = 1.24 g0.04 moles P x 30.97 g/mole = 1.24 g

Mass of a Mole of a Mass of a Mole of a CompoundCompound

►Example: SOExample: SO33

►What type of compound?What type of compound?►How many atoms of S and O?How many atoms of S and O?►Add up amus of S and OAdd up amus of S and O►32.1 amu + 16.0 amu +16.0 amu + 32.1 amu + 16.0 amu +16.0 amu +

16.0 amu = 80.1 amu16.0 amu = 80.1 amu►One mole SOOne mole SO33 weighs 80.1 g weighs 80.1 g

Practice: find the molar Practice: find the molar massesmasses

Find the molar mass ofFind the molar mass of►WaterWater►GlucoseGlucose►Carbon dioxide Carbon dioxide

PracticePractice

Q:How many moles of glucose are in 200 Q:How many moles of glucose are in 200 g?g?

►Molar mass of glucose is 180.18 g/moleMolar mass of glucose is 180.18 g/mole

A: 200g x mole/180.18 g = 1.11 molesA: 200g x mole/180.18 g = 1.11 moles

Q: How many molecules of glucose is this?Q: How many molecules of glucose is this?

6.02 x106.02 x102323 RP/mole x 1.11 moles = 6.7 x RP/mole x 1.11 moles = 6.7 x 10 10 2323 molecules glucose molecules glucose