Bellwork Prepare for Test Turn in Chapter 9 EQ Cellphones off and in backpack All back packs at the front of the classroom You need:

A piece of paper and a pencil Chapter 10 The Mole MAKE A NEW SECTION Chapter 10 Copy down the Main Idea and Essential Questions Main Idea: Chemists use the mole to count atoms, molecules, ions, and formula units

Essential Questions: Unit What is a mole and why do we use moles in chemistry? Lesson How are moles calculated?

How is percent composition calculated? What is the difference between an empirical and molecular formula? What does a chemical formula tell you? Chapter 10 Word Study Guide Word, Definition, Your Definition, Picture Optional Avogadros Number

Mole Representative particle Molar mass Empirical formula Molecular formula

Percent composition Launch Lab Complete Launch Lab (Work with a group of 2-3 plp) Page 319 Analysis #s 1-3 Homework Complete Word Study guide

Read Chapter 10 Outline Bellwork What is a mole? Be ready to present your answer to the class. Bellwork Mrs. Stewart is 5 feet tall.

If you have 10 of me, how far will it be if I am lined up from head to toe? If my son, Gunner, is 2 feet tall, how many of him would it take to cover the same distance? Apples Problem Here is how converting works Important: 1 dozen apples = 12 apples 1 dozen apples = 2.0 kg

1 dozen apples = .20 bushels 1. What is the mass of 90 average-sized apples if 1 dozen of the apples has a mass of 2.0 kg? Why use the mole? Chemists need a convenient method for accurately counting the number of atoms, molecules, or formula units in a sample of a substance. Because atoms are so small its impossible to count them directly.

Therefore, the MOLE was developed. The Mole SI base unit used to measure the amount of a substance. Mole = Mol Representative particle = any particle

Atom Molecule Formula unit Electron Ion

1 mol = 6.02 x 1023 representative particles Avogadros number Converting between Moles and Particles IMPORTANT 1 mol = 6.02 x 1023 representative particles Watch!!! How many particle of sucrose are in 3.5 mol of sucrose?

Your Turn Practice Problem 1 teach 2s Page 323 #s 1 and 3 2s teach 1s Page 323 #s 2 and 4

Hint: 4 has one extra step!!!! TRICKY! Particles to Moles Remember: 1 mol = 6.02 x 1023 representative particles How many moles of sucrose do you have if you contain 2.11 x 1024 molecules of sucrose? Classwork

Complete the following problems 2s teach 1s Page 324 # 5 1s teach 2s Page 324 # 6 Practice How many molecules are in 23 moles of oxygen?

How many moles are in 3.4 x 1023 molecules of H2SO4? How many molecules are there in 0.655 moles of C 6H14? How many moles are there in 2.35 x 1024 atoms of Fe? Journal By yourself Page 324 #s 13 and 14

Classwork 1. How many atoms are in 3.68 moles of CO2? 2. How many molecules are in 4.3 moles of N2O2? 3. If you have 3.98 x 1021atoms of Mg, how many moles do you have? 4. If you have 7.2 moles of Na+, how many ions do you have? 5.

How many formula units are in .35 moles of NaCl? 6. Determine the number of moles in 8.92 x 1023 ions of Fe+2. 7. Determine the number of atoms in 2.6 moles of Pb. 8. How many molecules are in 6.21 moles of SO2? 9. If you have 5.6 x 1021 formula units of PbSO4, how many moles do you have? 10.

Determine the number of moles in 5.78 x 1026 atoms of Hg. Molar Mass The atomic mass of an element expressed in grams, is the mass of one mole of the element. This is called Molar Mass Carbons molar mass is 12g Molar masses are rounded off to one place after the decimal point.

You know that 12.0 g is the molar mass of carbon, so 12.0g is 1 mol of carbon (6.02 X 1023 atoms of carbon). UNITS are g/mol Molar Mass of Compound To find the mass of a mole of a compound, you must know the formula of the compound.

EX: Formula of sulfur trioxide is SO3 1 atom of sulfur and 3 atoms of oxygen Calculate the mass of a molecule by adding atomic masses of atoms making up the molecule. S = 32.1 amu O = 3 X 16.0 = 48.0 amu SO, SO3 = 32.1 + 48.0 = 80.1 amu What does this mean?

80.1 g is the mass of 6.02 X 1023 molecules of SO3 80.1 g SO3 = 1 mol SO3 Classwork Find the molar mass of the following compounds PbSO4 N3O4

Al2O3 You measure 34.6 grams of H2O. How many moles are present in this sample of H2O? How many molecules? BELLWORK 1. How many moles of magnesium is 3.01 x 10 22 atoms of magnesium? 2. How many molecules are there in 4.00 moles of glucose, C6H12O6? 3. How many moles are 1.20 x 1025 atoms of phosphorous? 4. How many atoms are in 0.750 moles of zinc? 5. How many molecules are in 0.400 moles of N 2O5? Practice Problems 1.

The decomposition of Hydrogen peroxide (H2O2) provides sufficient energy to launch a rocket. What is the molar mass of hydrogen peroxide? 2. Find the molar mass of PCl3. 3. What is the mass of 1.00 mol of sodium hydrogen carbonate? Mole to grams conversions What is the mass of 4.56 mol of H2O?

There is 3.65 x 10-5 mol of NaCl, find the mass of the substance. How many moles are in 5.64 x 102 grams of Ca(OH)2? Practice Page 328 and 329 #s 15-18 Practice Problems Page 336 and 337

1s teach 2s #s 37 -39 2s teach 1s # 40 and 41 practice If I have 4.7 moles of CO2, how many grams do I have?

How many moles does SnO have with a mass of 765.9? Determine the number of moles in 56.34 grams of MgS. How many grams are in 8.23 moles of K 2O? You measure 34.6 grams of H2O. How many moles are present in this sample of H2O? How many molecules? Journal 1. Identify the conversion factors that we have discussed up until now.

2. Identify the 4 types of representative particles and give an example of each. 3. Find the molar mass of the following compounds 1. Cr2O3 2. MgS Practice

How many grams are in 3.2 moles of PbCl2? How many moles are in 3.45 x 1025 atoms of Na? Mole Conversions (GRADE) What is the mass of 2.0 moles of LiOH? How many moles of glucose does 1.2 x 1024 molecules represent? How many moles does 22.0 grams of CO2 represent?

How many moles does 56.0 grams of N2 represent? How many atoms does 2.2 x 101 moles of He represent? Two Step Process Page 331 #s 19, 20, 21 Atoms to mass

Mass to atoms or molecules TWO STEP PROCESS Representative particles to mass Change representative particles to moles Change moles to grams Mass to representative particles Change mass to moles

Change moles to representative particles (atoms or molecules) Bellwork: Mole conversions How many formula units are in 3.65 x 102 g of NaCl? How many molecules does 45.0 grams of C 6H12O6 represent? How many moles of water does 6.02 x 1023 molecules represent?

Convert 3.01 x 1023 molecules of C2H6 to moles. What is the mass of 7.23 x 1025 formula units of CuSO4 ? Practice How many grams are in 5.23 x 1023 molecules of SO3? How many grams are in 5.6 moles of KCl? If you have 4.3 moles of AgNO3, how many formula units

do you have? Avogadros Hypothesis States that equal volumes of gases at same temp and pressure contain equal # of particles. Particles are different sizes However, because the particles of gases are spread so far apart, the number of smaller particles are usually equal to the number of larger particles in a given area. Here is our LAST conversion Factor

At standard temperature and pressure 1 mol = 22.4 L (volume) or 6.02 X 10^23 representative particles = 22.4 L Example You collect 0.200 L H2 at STP, calculate the number of moles of H2. Practice

Determine the volume in liters, of 0.60 mol SO2 gas at STP. Determine the volume in liters, of 3.20 X 10-3 mol CO2. Determine the volume in liters, of 3.70 mol N2. More Practice How many total atoms are in 1.0 moles of H 2O ? How many moles of water does 6.02 x 1023 molecules represent?

How many moles does 80.0 grams of H2O represent? What is the mass of 5.0 moles of Ba(CN)2 ? At STP, what volume does 1.25 mol H 2 occupy? At STP, how many moles are in 43.3 L C2H6? Last Set!!! 1.

How many moles are 73.8 L Na ions? 2. Convert 5.00 moles of carbon trioxide to grams. 3. Convert 4.86 x 104g of Mg3N2 to moles. 4. A sample of NH3 gas occupies 75.0 liters at STP. How many molecules is this? Grade SHOW ALL YOUR WORK!!!!!

NO WORK = NO CREDIT 1. How many liters are in 5.4 moles of NaCl? 2. If you have 235.9 g of NH3, how many moles do you have? 3. How many molecules are in 3.2 moles of CO 2? 4. How many moles are in 2.68 x 1022 atoms of Mg?

5. There is 48.24 L of KBr, how many moles are there? 6. If you have 5.2 moles of C2H6, how many grams do you have? Grade Continued 7. How many molecules are in 1.2 moles of C6H12O6? 8. How many formula Units are in 2.3 x 1022 moles of Ca(OH)2 ? 9.

How many grams are in 5.26 x 1023 molecules of NO2? 10. How many liters are in 56.3 g of BaO? Understanding Check Answer the following questions: 1. What is a mole and why do we use moles in chemistry? 2. How are moles calculated?

1. 3 conversion factors? 2. Identify all the types of representative particles Percent composition Percent mass = mass of element x 100 ----------------------------mass of compound

Determine the percent composition of Sodium hydrogen carbonate (NaHCO3), also called baking soda. Practice Problems Page 344 #s 54-57 Complete these problems with your shoulder partner Classwork Find the percent composition of the following compounds

1s Teach 2s NaOH (NH4)2S 2s teach 1s N2S2 PbSO4 Homework

1. How many Mg atoms are in 3.24 moles of Mg? 2. How many liters of Mg are in 1.6 moles of Mg? 3. 2.68 x 1024 atoms of Cu equal how many moles? 4. How many grams are there in 1.5 x1025 molecules of CO2? 5. How many moles are 1.505 x 1023 NaCl formula Units?

6. How many moles are in 812 grams of Ca? 7. How many moles are 73.8 L Na ions? Bellwork Calculate the percent composition of the compounds that are formed from these reactions: 9.03 g of Magnesium combine completely with 3.48 g of Nitrogen.

29.0 g of Argon combine completely with 4.30 g of Sulfur. 222.6 g of Sodium combine completely with 77.4 g of Oxygen. Complete Practice Calculate the mass of the element in the given mass of compound: Mass of Hydrogen in 350 g C2H6 Mass of Oxygen in 20.2 g of NaHSO4

Mass of Hydrogen in 124 g of Ca(C2H3O2)2 Mass of Nitrogen in 378 g HCN Mass of Oxygen in 100 g H2O Empirical Formula The formula with the smallest whole number moles-ratio of the elements. May or may not be the same at the molecular formula.

WHY????? Step 1 Take percent sign and change to grams Step 2 - Solve for moles Step 3 if not in whole numbers divide each number by the lowest decimal. Step 4 if still not a whole number, multiply by the lowest

factor that would make it a whole number Example Determine the empirical formula for methyl acetate which is made up of 48.64% C, 8.16%H, and 43.20%O Complete Practice Problems 1s teach 2s 2s teach 1s

Problems 58 and 59 Problems 60-61 PAGE 346 Go over Pg 346 #s 58-61 More Practice 1. What is the empirical formula for a compound which contains 0.0134 g of iron, 0.00769 g of sulfur and 0.0115 g of oxygen? 2. Find the empirical formula for a compound which contains 32.8% chromium and 67.2% chlorine.

Practice Barry Um has a sample of a compound which weighs 200 grams and contains only carbon, hydrogen, oxygen and nitrogen. By analysis, he finds that it contains 97.56 grams of carbon, 4.878 g of hydrogen, 52.03 g of oxygen and 45.53 g of nitrogen. Find its empirical formula. Practice Problems 200.00 grams of an organic compound is known to contain 83.884 grams of carbon, 10.600 grams of hydrogen, 18.640 grams of oxygen. What is the empirical formula of the compound? Molecular Formula

Specifies the actual number of atoms of each element in one molecule or formula unit of the substance. Step 1 divide the experimentally determined molar mass by the mass of the empirical formula. Step 2 take the previous answer and multiply it times the subscripts of the empirical formula. Example The chemical analysis of succinic acid is 40.68% C, 5.08%H, and 54.24% O and has a molar mass of 118.1g/mol. Determine the empirical and molecular

formulas. Complete Practice With your shoulder partner complete the following: Page 350 #s 62-66 Also copy down the graphic organizer on page 347, figure 10.15 Study Guide How many moles are in 4.3 x 1022 atoms of Mg?

How many liters are in 4.6 moles on NaCl? How many grams are in 8.9 moles of MgCl2? How many liters are in 85.67 grams of KCl? Calculate the percent composition NaHSO4

222.6 g of Sodium combine completely with 77.4 g of Oxygen Study Guide Continued Whats the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen? A compound with an empirical formula of C2OH4 and a molar mass of 88 grams per mole, calculate the molecular formula A component of protein called serine has an approximate molar mass of 100 g/mole. If the percent composition is as follows, what is the empirical and molecular formula of serine?

C = 34.95 % H= 6.844 % O = 46.56 % N= 13.59 % Chapter 10 Study Guide 1. How many moles are in 34.6 L of BaO? 2. How many grams are in 4.6 moles of PbSO4? 3. How many molecules are in 6.5 x 10 3 moles of CO2? 4. If you have 2.68 moles of S2O3, how many atoms of S do you

have? 5. How many liters are in 4.39 x 10 22 atoms of Mg? 6. The compound methyl butanoate smells like apples. Its percent composition is 58.8% C, 9.8% H, and 31.4% O and its molar mass is 204 g/mol. What is its empirical formula? What is its molecular formula? 7. Find the molecular formula of ethylene glycol, which is used as antifreeze. The molar mass is 62 g/mol and the empirical formula is CH3O. 8.

Determine the molecular formula if you have 34.98g Al and 64.02g S and a molar mass of 300.6.