The Mole Ch 5.11 & Ch 6

Right Side – NOTES ONLY Title and Highlight TN Ch 5.11 Date Topic: EQ: Book Questions: Write Question out (left side of red line) and answer it (Highlight answer) based on from what you read. Notes: Write out the notes from my website. You may use different color pens. Use Bullets or Number notes. Space out your notes so you can add any additional into during lecture. NO HIGHLIGTING, UNDERLINING, etc WE WILL DO OUR FOCUS NOTES TOGETHER Summary: Write 2-3 sentences (end of notes) from what you learned from reading, notes, and/or lecture.

LEFT Side – PICTURES, PRACTICE PROBLEMS, ETC Title and Highlight TN Ch 5.11 DRAW ANY PICTURES, FIGURES, AND WRITE OUT ANY PRACTICE PROBLEMS/QUESTIONS. WE WILL ANSWER THEM TOGETHER. LEAVE SPACES SO WE CAN ANSWER QUES.

Ch 5.11 Topic: Formula Mass EQ: How can you calculate the formula mass for any compound? READ Ch 5.11 (pg. 148-149) Write Questions & Answer Questions #24 (notes side) Highlight answer

Formula Mass: The Mass of a Molecule or Formula Unit For any compound, the formula mass is the sum of the atomic masses of all the atoms in its chemical formula (units = amu – atomic mass unit):

Formula Mass Rules 1. Count the # of atoms for each element in compound 2. Multiply each by their mass (units are amu) on P.T. (use exact # on PT) 3. Add up all Masses (WARNING!!! Don’t forget sig fig rules & units.) What is the formula mass for CaCl2 Ca 1 x 40.078 amu = 40.078 amu + Cl 2 x 35.453 amu = 70.906 amu = 110.984 amu CaCl2

Left side Practice #1 (leave 5 spaces between each problem to solve problem during lecture) Find the formula mass for the following ionic compounds a. MgSO4 b. KCN c. Ca(OH)2

Ch 6.1-6.3 (Part 1) Topic: Counting Atoms EQ: What is a mole? 6.02 x 1023 Ch 6.1-6.3 (Part 1) Topic: Counting Atoms EQ: What is a mole? READ Ch 6.1-6.3 (pg. 165-168 stop at “converting grams ad moles) Write Questions & Answer Questions #1-4 (notes side) Highlight answer

6.1-6.3 Conversion factors What is a conversion factor? It relates how an object compares to another. Usually one item is set to equal 1. Examples: 1 min = 60 sec 1 year = 365 days 1 doz eggs= 12 eggs 1 pound = 16 ounces

Atoms by the Gram With atoms, we must use their mass as a way to count them. Atoms - too small & too many to count individually. We need a larger # because atoms are so small. Chemist’s use mole (mol).

What is the Mole? A large amount!!!! VERY Avogadro’s number = 602 billion trillion 602,000,000,000,000,000,000,000 6.02 X 1023 (in scientific notation) This number is named in honor of Amedeo Avogadro (1776 – 1856), 1 mol = 6.02  1023 items (units change) A large amount!!!! VERY

Video: How big is a mole? (ed.ted.com)

One mole of anything is 6.02 × 1023 units of that thing. One mole of marbles = 6.02 × 1023 marbles. One mole of sand grains = 6.02 × 1023 sand grains. The value of the mole is defined as being equal to the number of atoms in exactly 12 g of pure carbon-12. (Very important) This definition of the mole establishes a relationship between mass (grams of carbon) and number of atoms (Avogadro’s number).

HOW LARGE IS IT??? 1 mole of hockey pucks would equal the mass of the moon! (Moon mass 7.3 x 1022 kg) 1 mole of basketballs would fill a bag the size of the earth!

Just How Big is a Mole? Enough soft drink cans to cover the surface of the earth to a depth of over 200 miles. If you had Avogadro's number of unpopped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles. If we were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole.

A Mole of Particles 1 mole = 6 A Mole of Particles 1 mole = 6.02 x 1023 representative particles (see list of units below) = 6.02 x 1023 C atoms = 6.02 x 1023 H2O molecules = 6.02 x 1023 NaCl formula units 1 mole C 1 mole H2O 1 mole NaCl Representative Particles: Atom = 1 element Formula unit (f.u.) = Ionic Compound Molecule = Molecular Compound Ion = charge atom

How many molecules are in 2.50 moles of C12H22O11? Left side Practice #1 (leave 5 spaces between each problem to solve problem during lecture) How many molecules are in 2.50 moles of C12H22O11?

Left side Practice #2 (leave 5 spaces between each problem to solve problem during lecture) a. Number of atoms in 0.500 mole of Al b.Number of moles of S in 1.8 x 1024 atoms S

6.02 x 1023 Ch 6.3 (Part 2) Topic: Mass & Moles EQ: How do you convert grams and moles of an element? READ Ch 6.3 (pg. 168-170) Write Questions & Answer Questions #5-7 (notes side) Highlight answer

HINT - This will help you answer ques #7 HINT - This will help you answer ques #7!! These pictures have the same number of atoms. The weight of one mole of atoms changes for different elements.

Molar Mass for an Element The molar mass of any element—the mass of 1 mol of that element. (Cool part is that it’s the same calculation as gram formula mass – Ch 5.11) Need to see the difference: 1 Cu atom has atomic mass = 63.55 amu. 1 mol of Cu atoms has mass of 63.55 g. ……Do you see the difference????

Mass & Mole Molar Mass - 1 mole equals the sum of the atomic masses in grams ( not amu). Need Periodic Table!!!! molar mass Mass (g) Moles (mol) 1 step conversion!!

Learning Check! Find the molar mass from PT (DON’T ROUND!!!) 1 mole of Br atoms 1 mole of Sn atoms = 118.710 g

How many moles of carbon are in 26 g of carbon? Left side Practice #1 (leave 5 spaces between each problem to solve problem during lecture) How many moles of carbon are in 26 g of carbon?

Left side Practice #2 (leave 5 spaces between each problem to solve problem during lecture) How many grams of Al are in 3.00 moles of Al?

6.02 x 1023 Ch 6.3 (Part 3) Topic: Mole Conversions EQ: How do you convert grams, moles, and atomsof an element? READ Ch 6.3 (pg. 171-172) No Questions

C. Molar Conversions – 2 step molar mass 6.02  1023 MASS IN GRAMS MOLES NUMBER OF PARTICLES Everything must go through Moles!!!

Left side Practice #1 (leave 5 spaces between each problem to solve problem during lecture) How many atoms of Cu are present in 35.4 g of Cu? Remember… 6.02 X 1023 atoms = 1 mole = molar mass (g)

How many atoms of K are present in 78.4 g of K? Left side Practice #2 (leave 5 spaces between each problem to solve problem during lecture) How many atoms of K are present in 78.4 g of K? Remember… 6.02 X 1023 atoms = 1 mole = molar mass (g)

How many grams of Ca are present in 5.23 x 1024 atoms Ca? Left side Practice #3 (leave 5 spaces between each problem to solve problem during lecture) How many grams of Ca are present in 5.23 x 1024 atoms Ca? Remember… 6.02 X 1023 atoms = 1 mole = molar mass (g)

6.02 x 1023 Ch 6.4 Topic: Moles of Compounds/Molecules EQ: How do you convert grams and moles of comp./molecule? READ Ch 6.4 (pg. 172-174) Write Questions & Answer Questions #8 (notes side) Highlight answer

Molar Mass of Molecules and Compounds Molar mass is the mass of 1 mol of molecules (units used for only molecules) or formula units (units used for only ionic compounds) of that compound. Just like Ch 5.11!!! Just different units because of moles 1 mole of CaCl2 Ca 1 x 40.078 g = 40.078 g + Cl 2 x 35.453 g = 70.906 g = 110.984 g/mol CaCl2

Molar Conversions Everything must go through Moles!!! molar mass 6.02  1023 MASS IN GRAMS MOLES NUMBER OF PARTICLES (g/mol) (particles/mol) Everything must go through Moles!!!

Find the mass of 2.1  1024 formula units of NaHCO3. Left side Practice #1 (leave 5 spaces between each problem to solve problem during lecture) Find the mass of 2.1  1024 formula units of NaHCO3.

Find the formula units of 51.5g of NaHCO3. Left side Practice #2 (leave 5 spaces between each problem to solve problem during lecture) Find the formula units of 51.5g of NaHCO3.

6.02 x 1023 Ch 6.5 Topic: Moles to Mole conversions EQ: How do you convert moles to compounds to moles of elements? READ Ch 6.5 (pg. 175-179) Write Questions & Answer Questions #10 (notes side) Highlight answer

Hint – this slide with help you with book question #10 The relationships in a chemical formula allow us to convert between moles of the compound and moles of an element (and vice versa).

Find the number of moles of O in 1.7 mol CaCO3. Left side Practice #1 (leave 5 spaces between each problem to solve problem during lecture) Find the number of moles of O in 1.7 mol CaCO3.

Left side Practice #2 (leave 5 spaces between each problem to solve problem during lecture) Find the moles of sodium in 15 g of NaCl.

Day 2 - Ch 6.5 continue (same notes as yesterday) 3 step conversion Get out conversion chart to add a new box! To play the movies and simulations included, view the presentation in Slide Show Mode. 6.02 x 1023

How many grams of O are present in 78.1 g CO2? Left side Practice #3 - 3 step conversion (leave 5 spaces between each problem to solve problem during lecture) How many grams of O are present in 78.1 g CO2?

6.02 x 1023 Ch 6.6-6.7 Topic: Mass Percent Composition EQ: How do you find the percent composition for an element in a compound? READ Ch 6.6-6.7 (pg. 180-182) Write Questions & Answer Questions #12 (notes side) Highlight answer

What is the Percent Composition of the Elements in our Universe: Left side – Draw and color What is the Percent Composition of the Elements in our Universe:

What is the Percent Composition of Earth’s Crust? Left side – Draw and color What is the Percent Composition of Earth’s Crust?

What is the Percent Composition of the Human Body? Left side – Draw and color What is the Percent Composition of the Human Body?

The mass percent composition, or percent composition, of an element is the element’s percentage of the total mass of the compound. You use this calculation everyday….called your grades!!!

Rules for Calculating Mass Percent Composition Step 1: Calculate the molar mass of the compound. Step 2: Divide each elements total mass by the molar mass of the compound. Step 3: Convert the decimal to a % by multiplying by 100. Step 4: Al ways check your work!!!! All element %’s should equal 100%.

Left side Practice #1 (leave 5 spaces between each problem to solve problem during lecture) Find the % composition of each element in Na3PO4

Left side Practice #2 (leave 5 spaces between each problem to solve problem during lecture) Find the % composition of CARBON in C4H10

6.02 x 1023 Ch 6.8 Topic: Empirical Formula (E.F.) EQ: How do you determine the E.F. from masses & percents? READ Ch 6.8 (pg. 183-185) Write Questions & Answer Questions #13-14 (notes side) Highlight answer

2 Types of Formulas Empirical and Molecular Formulas give the numbers of atoms or moles of each element always in a whole number ratio (the law of definite proportions). 1. Empirical Formula: The formula of a compound with the smallest whole number ratio of the atoms present.

Rules to obtain an Empirical Formula Determine the mass in grams of each element present. If %’s are given, check to see if %’s equal 100%. If yes, then the 100%=100g. So, change %’s to grams. 2. Calculate the number of moles of each element. 3. Divide each by the smallest number of moles to obtain the simplest whole number ratio. If whole numbers are not obtained* in step 3, multiply through by the smallest number that will give all whole numbers (**See bottom of page 185 for help with what # to multiply with to get whole subscript number) * Be careful! Do not round off numbers prematurely

Left side Practice #1 (leave 5 spaces between each problem to solve problem during lecture) A sample of a brown gas, a major air pollutant, is found to contain 2.34 g N and 5.34g O. Determine the empirical formula for this substance.

Left side Practice #2 (leave 5 spaces between each problem to solve problem during lecture) A substance has the following composition by mass: 60.80 % Na ; 28.60 % B ; 10.60 % H What is the empirical formula of the substance?

6.02 x 1023 Ch 6.9 Topic: Molecular Formula (M.F.) EQ: How do you determine the M.F. from the E.F.? READ Ch 6.8 (pg. 186-187) Write Questions & Answer Questions #15 (notes side) Highlight answer

2 Types of Formulas 2. Molecular Formula: The formula that states the actual number of each kind of atom found in one molecule of the compound. (biggest ratio)

Rules to obtain a Molecular Formula Need Empirical Formula first (look at rules from Ch 6.8)…Solve for it!! Calculate the molar mass of E.F. Book MUST give you the molar mass of Molecular Formula. To find M.F….. molar mass of M.F. = whole number ( E.F. ) = M.F. molar mass of E.F.

Left side Practice #1 (leave 5 spaces between each problem to solve problem during lecture) A compound has an empirical formula of NO2. The colorless liquid, used in rocket engines has a molar mass of 92.0 g. What is the molecular formula of this substance?