Moles are a Chemist Best FriendChapter 10

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Objectives: Moles are a Chemist Best Friend• I can identify what a mole is in chemistry.

• I can convert between representative particles of matter and moles.

• I can convert between the mass of matter and moles.

• I can convert between the volume of matter and moles.

Chemistry (4/8)Infinite Campus Update: • Chemical Reaction Exam (raw avg. 62%)• Chemical Reaction Study Guide (10pts.)-optionalObjectives:• Address Chemical Reaction Exam• Discuss Science Reflection Article• Identify what a mole is in chemistry.Homework:• Review Chemical Rxtn. Notes/Complete Study Guide• Science Reflection Article-due Friday• Need calculator for new unit- The Mole

Science Reflection Article• Select one article to read on my webpage:a. “Drivers, Start Your (Electric) Engines!”b. “Green Gasoline: Fuel From Plants”• Complete annotation and evaluation questions. • Due: Friday, April 12th

Chemical Reaction Exam

• Chemical Exam Make-up Questions-Fri.

Chemistry (4/9)Objectives:• Review endothermic vs. exothermic energy

diagrams• Identify what a mole is in chemistry.

Homework:• Mole Problems. (Bring calculator for this unit!)• Review chemical reaction notes/practice problems.• Science Reflection Article-due Friday

• Chemical Reaction Make-up Qts-Friday

Energy DiagramDoes this represent an endothermic or exothermic reaction?

(H)

(time)

Energy Diagram• H reactant > H product• More energy will be released in this reaction• Small activation energy

(H)

(time)

Energy Diagram

Activation Energy

Does this represent an endothermic or exothermic reaction?

(H)

(time)

Endothermic Energy Diagram

Activation Energy

• H reactant < H product•More energy is absorbed in this reaction•Large activation energy

Chemistry (4/9)Objectives:• I can identify what a mole is in chemistry.• I can convert between representative particles

of matter and moles.

Homework:• Chemical Reaction Review-due Fri.• Science Reflection Article-due Fri.

Moles are a Chemist Best FriendChapter 10

nclark.net

Objectives: Moles are a Chemist Best Friend• I can identify what a mole is in chemistry.

• I can convert between representative particles of matter and moles.

• I can convert between the mass of matter and moles.

• I can convert between the volume of matter and moles.

Measuring MatterWhat are three ways we can measure matter? 1.

2.

3.

hermitwoods.com

Measuring Apples

stockphotos.it

flickr.com

www.123rf.com

Grouping Matter• Easy way to measure all matter. r

Dozen dougnuts=

Gross of pencils=

Ream of paper = Byte of stored information=

Grouping Representative Particles• How would scientists group representative

particles of matter?

Representative particles: the substances that make-up matter.

nclark.net

Classification of Matter

Grouping Representative Paraticles• How would we group representative particles that

make-up matter?

Representative particles: substances that make-up matter.

(atoms, molecules or ionic compounds)

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Grouping Representative Particles

1 mole = 6.02x1023 representative particles (Avogadro’s Number)

•“The Mole is a Unit” song (nclark.net)

A mole is a unit of measurement that is used to group representative particles.

Mole Conversion Map

http://mysite.cherokee.k12.ga.us

Chemistry (4/10)Objectives:• I can identify what a mole is in chemistry.• I can convert between moles and representative

particles of matter.

Homework:• Mole Conversion Problems-due Thurs.• Chemical Reaction Review-due Fri.• Science Reflection Article-due Fri.

Bell Ringer: Moles

1. a. What is a representative particle? b. Give two examples of representative particles.

2. a. What is a mole? b. How many atoms of Cu are in a mole of Cu?

Mole Conversion Map

http://mysite.cherokee.k12.ga.us

Converting Moles to Representative ParticlesEx. Propane (C3H8) is a gas used for cooking and

heating. How many molecules of propane is equal to 2.4 moles of propane?

Mole Conversion Map

http://mysite.cherokee.k12.ga.us

Convesion: Representative Particles to Moles Ex. Magnesium is a light metal used in the

manufacture of aircraft and automobile wheels. How many moles of magnesium equals 1.25x1023

atoms of magnesium?

Mole Conversion Map

http://mysite.cherokee.k12.ga.us

Conversion: Mole-Representative Particles Homework Problems

A Mole is a Chemist Best Fried wks.When calculating mole conversions….• Show work so errors can be identified and

corrected.• Multiply what your given by the conversion

fraction. They are NOT equal or proportional to one another.

• If dividing scientific notation values, place parenthesis around the value in the denominator when plugging in calculator.

• Express answer with correct number of significant figures (sigs.); units.

Chemistry (4/11)Objectives:• I can convert between moles and representative

particles of matter. • I can convert between moles and mass of matter.Homework:• Mole Conversion Problems-Fri.• Chemical Reaction Review-due Fri. (optional)• Science Reflection Article-postpone Mon. Friday:Chemical Reaction Make-up Qts. (16qts )

Conversion: Mole-Representative Particles Homework Problems

Converting Moles to Mass• How do we convert from moles to mass of a

substance?

Mole Conversion Map

http://mysite.cherokee.k12.ga.us

Conversion: Moles- Mass• Mole-Mass Conversion: 1 mole of a substance = molar mass of the substance

Molar Mass of an Element• molar mass of element = atomic mass of element• Round atomic mass to tenths place.

Ex. A mole of sulfur (S) has a molar mass of?

Ex. A mole of sodium (Na) has a molar mass of?

Molar Mass of a Compound• molar mass of compound = sum of the elements’

atomic masses in the compound.• Need chemical formula to calculate the molar

mass of a compound.Ex. A mole of NaCl has a molar mass of?

Ex. A mole of H2O has a molar mass of?

Molar Mass of Compounds

Mole-Mass Conversions

Ex. How many moles are in 2.5 grams of Cu?

Ex. How many grams are in 3.8 moles of FeO?

Chemistry (4/15)Due Today:• Science Reflection Article qts.Infinite Campus Update:• Chemical Reaction Make-up Qts.(optional)• Moles are a Chemist’s Best Friend Wks. (5pts.)Objectives: • Calculate molar mass of a substance.• Convert between moles and mass of a substance.Homework: • Mole Packet

Bell Ringer: Chemistry1. What is the representative particle for each substance

below? (atom, ionic compound, or molecule)

a. Na2O b. Fe c. H2 d. Ne

2. How many atoms are in 2.5 moles of copper?

3.a. What is the molar mass of silver, Ag?

b. What is the molar mass of Al2(CO3)3?

Chemistry (4/16)

Objectives: • Calculate molar mass of a substance.• Convert between moles and mass of a substance.

Homework: • Mole Conversion Worksheet

*Quiz: Friday -mole conversions

Conversions: Mole-MassEx. How many moles of iron (III) oxide are contained

in 92.2g of pure Fe2O3?

Ex. How many grams are in 2.68 moles of Fe2O3?

Mole-Mass Conversions

Conversions: Mole-Mass• 1 mole = molar mass of substanceEx. When iron is exposed to air, it corrodes to form

red-brown rust. How many moles Fe2O3 are contained in 92.2g of pure Fe2O3?

Chemistry (4/17)Objective: • Discuss qts. over homework (mole conversions)• Mole Conversion Lab

Homework:• Complete Mole Conversion Lab post questions.

Mole Conversions

Mole Conversion Lab

Purpose: Practice mole conversions with substances in the lab.

Hypothesis: How many particles are in a tablespoon of each of the following substances?

• H2O

• Ca(CO3)

• NaCl

Mole Conversion Map

http://mysite.cherokee.k12.ga.us

Chemistry (4/18)Objective: • Calculate 2-Step Mole Conversions• Address questions over Mole Conversion Lab

Homework:• 2-Step Mole Conversion Problems

*Quiz tomorrow: mole conversions

2-Step Mole ConversionsEx. How many grams are there in 2.4x1013 atoms of

Carbon?

Ex. How many molecules are in 48.4 grams of Ca(PO4)2 ?

Mole Conversion Map

http://mysite.cherokee.k12.ga.us

Chemistry (4/19)Objective: • Discuss 2-Step Mole Conversion Problems (hmwk)• Mole Conversion Quiz• Calculate % Composition of a Compound

Homework:• % Composition of a Compound• Chemical Quantities Study Guide

*Chemical Quantities Exam: Wed., April 19th

2-Step Mole Conversions-Key

3. 1.3x1023 atoms4. 1.0x1024 molecules5. 410 grams6. 210 grams7. 120 grams8. 3.92x1023 molecules9. 310 grams10. 1.1x1024

Chemistry (4/22)Objective: • Calculate % Composition of a Compound• Discuss Mole Conversions• Take Mole Conversion Quiz

Homework:• % Composition of a Compound worksheet and lab.• Chemical Quantities Study Guide

*Chemical Quantities Exam: Wed/Thurs., April 24th/25th

Chemistry (4/22)Objective: • Calculate % Composition of a Compound• Complete Mole Lab• Discuss Mole Conversion Quiz and Study Guide

Homework:• % Composition of a Compound worksheet and lab.• Chemical Quantities Study Guide

*Chemical Quantities Exam: Wed., April 24th

Chemistry (4/22)Infinite Campus Update: • Mole Conversion Worksheet (10pts.)• Science Article Questions (15pts.)

Midterm Grades Posted: 4/24

Percentage Composition of a Compound

Percentage Composition of a Compound• % by mass of each element in a compound

• How do we calculate % composition of a compound?

Percentage Composition of a Compound

Percentage Composition of a Compound• % by mass of each element in a compound

What is the percent composition of NaCl?

Chemistry (4/23)Objectives: • Review for Chemical Quantities Exam

*Chemical Quantities Exam : April 24th/25th

Homework: Complete study guide-key on my webpage

Chemistry (4/23)Objectives: • Review for Chemical Quantities Exam

*Chemical Quantities Exam : April 24th (tomorrow)

Homework: Complete study guide-key on my webpage

Chemical Quantities: Bell Ringer1. How many moles are in 7.4 grams of Ba(OH)2?

2. How many grams are in 3.8x1019 atoms of C?

3. Calculate the % composition of Al(NO3)3.

4. How many grams of N are in 5.4 grams of Al(NO3)3?

Chemical Quantities: Bell Ringer1. How many moles are in 7.4 grams of Ba(OH)2?

2. How many grams are in 3.8x1019 atoms of C?3. Calculate the % composition of Al(NO3)3.

4. How many grams of N are in 5.4 grams of Al(NO3)3?

Chemistry (4/24)Infinite Campus:•Mole Lab (15pts.)•Mole Worksheet (10pts)•Science Article Qts. (15pts.)Objectives: •Chemical Quantities Test•Introduce Hydrate LabTomorrow:Hydrate Lab

Percent Composition of Compound

Percentage Composition of a Compound

Percentage Composition of a Compound• % by mass of each element in a compound

• How many grams of Na are in a 3.5 gram sample of NaCl?

• How many grams of Cl are in a 20 gram sample of NaCl?

Mole Quiz

Study Guide

% Composition from Chemical Formula

% mass of element =

Ex. Propane, C3H8 is one of the compounds obtained from petroleum and is used to fuel homes and gas grills. Calculate the percent composition of propane.

% Composition as a Conversion Factor• Use % composition data to calculate the mass of

an element in a specific sample of that compound.

• Ex. What is the mass of Al in 6.5 g of Al(NO2)3 ?

% Composition as a Conversion Factor

•What is the mass of Al in 6.5 g of Al(NO2)3 ?

% Composition as a Conversion Factor

•What is the mass of N in 6.5 g of Al(NO2)3 ?

•What is the mass of O in 6.5 g of Al(NO2)3?

Bell Ringer: Chemical Quantities1. How many grams are in 5.0 moles of Cs3N ?

2.How many moles are in 3.7x1021 cmpds. of NaCl?

3. What is the % composition of Cu2(SO4)?

4. How many grams of Cu are in 9.8 g of Cu2(SO4)?

Empirical vs. Molecular FormulasMolecular: Actual whole-number ratio of atoms in

compound. Ex. Glucose molecular formula= C6H12O6

Empirical: Smallest whole-number ratio of atoms in a compound.

Ex. Glucose empirical formula = CH2O

Molecular Empirical

H2O2 (hydrogen peroxide, antiseptic)

C2H2 (fuel used in welding)

C6H6 (styrofoam)

N2O4 (rocket propellant)

CO2 (carbon dioxide)

What is the molar mass of Cr3N2?

• How many moles of FeO are in 5.4x1026 compounds of FeO?

How many grams of Be3(PO3)2 are in 7.84 moles of Be3(PO3)2 ?

How many atoms of Br are in 3.6 moles of Br?

Empirical vs. Molecular FormulasChemical Name Formula Classification

CH

C2H2 (acetylene)

C6H6 (benzene)

CH2O (methanol)

C2H4O2

(ethanoic acid)

C6H12O6 (glucose)

Calculate Empirical Formula• Use % composition data and molar mass of

elements .Ex. A compound is analyzed and found to contain

25.9% N and 74.1% O. What is its empirical formula?

25.0g N x ( 1mole N/14gN ) = 1.85 moles N74.1 g O x (1moleO/16 g O) = 4.63 moles O

Numbering Matter

What are some familiar terms we use to number matter?

Moles Representation

• A mole can be used to represent anything.• Ex. A mole of moles = 6.02x10 23 moles of moles

Bell Ringer1. What do the following terms have in common?

pair, dozen, byte, and mole?

2. What does 1 mole equal? Is it a big or small value?

3. Give a practical example using the term mole.Ex. 1 mole of carbon atoms.

Mole and Particles

1 mole = 6.02x1023 particles (atoms, ions, or compounds)

• How many Li atoms are in 4.0 moles?

• How many Li1+ ions are in 2.0 moles?• How many moles are in 1.35x1020 of H2O molecules?

Where did they get Avogadro’s Number?

• Scientist discovered that 12g of Carbon was equal to one mole. 12 g = molar mass of C

• Scientist discovered that 35g of Chlorine was also equal to one mole. 35g = molar mass of Cl

• Is there a chemistry term we can associate with molar mass?

Molar Mass

• Molar mass is the mass of an element that equals 1 mole.

Hydrate Lab Cu(SO4) . H2O ----> Cu(SO4) + H2O

Use the equation above to help answer the following questions:

1.What is the hydrate salt in this equation?2.What is the anhydrous salt in this equation?3.What is the difference between a hydrated salt

and an anhydrous salt?4.Is this a physical or chemical reaction?5.What did you calculate the chemical formula

for the hydrated salt to be?

Copper Sulfate Hydrate

Mole Map

number ofrepresentative

particles

mass

1 mol22.4L

22.4L1 mol

6.02 x 10 particles1 mol

23

6.02 x 10 particles231 mol

1 molmolar mass

molar mass1 mol

moles

volumeat STP

Mole and Mass Conversion

• 1 mole of Mg is equal to how many grams of Mg?

• 4 moles of N2 is equal to how many grams of N2?

• 2.5 moles of CH4 is equal to how many grams of CH4?

Mole and Mass Conversions

• How many moles is equal to 172 g of NaCl?