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Ch 3.3 and Ch 9.  Scientific Notation—great for very large or very small numbers Ex 1: Hope Diamond has 460,000,000,000,000,000,000,000 atoms Ex 2:

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Presentation on theme: "Ch 3.3 and Ch 9.  Scientific Notation—great for very large or very small numbers Ex 1: Hope Diamond has 460,000,000,000,000,000,000,000 atoms Ex 2:"— Presentation transcript:

1 Ch 3.3 and Ch 9

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3  Scientific Notation—great for very large or very small numbers Ex 1: Hope Diamond has 460,000,000,000,000,000,000,000 atoms Ex 2: 1 Carbon atom of the Hope Diamond has a mass of 0.00000000000000000000002 g ◦ 4.6 x 10 23 atoms = Hope Diamond atoms (not 45 x 10 22 ) ◦ 2 x 10 -23 grams = carbon atom mass  4.6 and 2 are the coefficients of the number  The 10 to the raised power represents the number of decimal places

4 1. 3,000,000,000 2. 4500 3. 0.000023 4. 438,000 5. 0.00245 6. 0.056  3x10 9  4.5x10 3  2.3x10 -5  4.38x10 5  2.45x10 -3  5.6x10 -2

5  (2.3 x 10 3 )(8.2 x 10 4 ) =  (7.34 x 10 -5 )(8.221 x 10 -2 ) =  9 x 10 6 ÷ 4.00 x 10 3 =  6.23 x 10 3 + 2.5 x 10 5 =  Think on this…do you need to write down EVERY single number the calculator gives you??? ◦ Sig figs!

6  Meter for length ◦ Use a meterstick to measure  Kilogram for mass (1 kg = 2.2 lbs) ◦ Weight is NOT the same thing as mass! ◦ Use a scale to measure  Kelvin for temperature ◦ K = o C + 273 ◦ 0 K = absolute zero ◦ Use a thermometer to measure ◦ o C is another option, but not Fahrenheit (in the metric system)  Second for time ◦ Use a stopwatch to measure  Mole for the amount of substance ◦ We will talk about mole next chapter  Liter for volume ◦ Use a graduated cylinder to measure  joule or calorie for energy ◦ We don’t discuss this much in this class…

7  Conversion factors ◦ Values can often be expressed in more than one form  $1 = 4 quarters = 10 dimes = 20 nickels = 100 pennies  1 meter = 100cm = 1000mm = 0.001km ◦ equal values can be shown as a ratio equal to 1; such ratios are called conversion factors…  conversion factors are useful for solving problems in which given measurements must be expressed in some other unit.

8  Dimensional Analysis: a way to problem solve/calculate that uses conversion factors to solve problems.  Calculate how many seconds old you are?  If you can run the 100 m dash in 12.72 seconds, how many kilometers per hour is that?

9 Ex: Convert 1,000 kilometers into millimeters. Ex: A boat is to be three hundred cubits long, fifty cubits wide and thirty cubits high. How big is that in feet? ◦ HINT: 1 cubit = 45 cm; 1 foot = 30 cm

10  How many minutes are there in one week?  How many seconds are in one year?  It takes 12 ounces of sugar to make 1 batch of cookies. How many batches of cookies can be made from a 5 pound bag of sugar?

11 Ch 3.3 and Ch 9

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13 Or these… Or these…

14  We live in a quantitative world… ◦ How much do you make? ◦ How old are you? ◦ How long is this class? ◦ How many questions are on the final exam?  How much? How many?  We measure by COUNT, MASS, and/or VOLUME.

15  1 pair of shoes = 2 shoes  12 cupcakes =1 dozen cupcakes  1 reem of paper = 500 sheets  Each of these could be used as a conversion factor  If there are 800 students at LACHSA, how many dozen are there? Calculate it!  MOLES is a unit like these…it represents a certain number!!

16  1 mole = 6.022 x 10 23 of anything  Moles are handy when there are large quantities of matter. ◦ What if you needed to count the number of grains of sand in 10 grams???  1 mole of apples = 602,200,000,000,000,000,000,000 apples ◦ Thank goodness for scientific notation!  1 mole of $$ = $6.022 x 10 23  1 mole of cheerios = 6.022 x 10 23 cheerios

17 A mole is 6.02 x 10 23 of anything! A mole of basketballs would just about fit into a ball bag the size of the Earth! So just how big is a mole? Draw a 1 inch square box on your paper: When the teacher says “go” put as many dots in that box as you can in 30 seconds. Now, count the dots. (A highlighter or differently-colored pen may be useful.) x2, What is your dot making rate in dots/minute? _____________ Working at this rate, how many dots could you make in an hour? _____________________ If a student can make 303 dots per minute, it will take 3.78 x 10 15 years to make a mole of dots! Even if 25 students in the class worked at this rate, it would take the class 1.51 x 10 14 years, making dots 24-7, to make a mole of dots!

18  1 mole of Fe atoms = 6.022 x 10 23 atoms  1 mole CO 2 molecules= 6.022x10 23 molecules  1 mol NaCl molecules= 6.022x10 23 molecules  Why the different units for Fe vs. CO 2 vs NaCl?? 6.022x10 23 is referred to as Avogadro’s Number

19  1 mole of carbon = 12.0 grams  1 mole of Fe = 55.9 g  1 mole of S = 32.1 g/mol  Look at a periodic table, where are these numbers coming from?  for our purposes, we will round to 1 decimal place for each atomic mass  Atomic mass= mass of 1 mole of the atom  Molar mass= atomic number = g/mol  Unit can be g or g/mol

20 1. What is the mass of 1 mole of any element? it’s atomic mass 2. Where do you find it? Periodic table…(decimal value) 3. What is its unit of measurement? Grams or grams/mol

21  To find the mass of 1 mole of a compound, you must know the formula of the compound. Molar masses of chemical compounds = the sums of the molar masses of all the atoms in one molecule of that compound. Ex: calculate the molar mass of 1 mole of carbon dioxide.

22  Calculate the mass of 1 mole of Sodium Chloride (salt) ◦ Gotta know the formula: NaCl ◦ Na = 23.0 g x 1 atom in the compound = 23.0 g ◦ Cl = 35.5 g x 1 atom in the compound = 35.5 g ◦ Total = 23.0 + 35.5 = 58.5 g ◦ The molar mass of NaCl = 58.5 g ◦ 1 mole of NaCl = 58.5 g

23 1. Calculate the molar mass of water. 18.0 g/mol 2. Calculate the mass of 1 mole of PCl 3. 137.5 g/mol 3. Calculate the molar mass of Zn(NO 3 ) 2. 189.4 g/mol

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25 Mass g Mole # of Particles (atoms, molecules) 1mol _ 6.022x10 23 atoms molar mass 1mole molar mass 6.022x10 23 atoms 1mole Pg 84 Use to convert between mole and mass and amount of particles

26 Mass g Mole # of Particles (atoms, molecules) Pg 84 Use to convert between mole and mass and amount of particles 1 mol = 6.022x10 23 particles molar mass (g) = 1 mol

27  When we convert moles to: molecules, atoms, formula units, etc, we use the following conversion factors:

28  How many molecules are in 2.00 moles of sucrose? 2.00 moles x = 1.20x10 24 molecules

29  How many moles are in 2.33 x 10 24 molecules of water?  How many atoms are in 2.95 moles of Au? 3.87 moles 1.77 x 10 24

30  Warm up: Correct intro to mole worksheet  Correct HW  Practice gram to mole  Practice gram to particle  Chalk activity

31 Mass g Mole # of Particles (atoms, molecules) Pg 84 Use to convert between mole and mass and amount of particles 1 mol = 6.022x10 23 particles molar mass (g) = 1 mol

32  We use molar mass as a conversion factor: Ex: grams to moles  Calculate the number of moles in 75.0 g dinitrogen trioxide.

33 1. Find molar mass of N 2 O 3 2. Use conversation factor 75.0g x 14.01x2 + 16.00x3 = 76.02g/mole 1 mole 76.02g =.986mol N 2 O 2

34  The molar mass can be used to convert between mass and moles. Need to be able to go both ways…from moles to mass or mass to moles.  You need 3.0 moles of NaCl for a lab experiment. ◦ How are you going to measure out 3.0 moles? Can’t do it on a scale… ◦ You need to convert from moles to grams.  In order to convert, you need to know the mass of 1 mole of NaCl  Now solve…

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36 1. Calculate the mass, in g, of 0.250 moles of sodium chloride. 2. Calculate the number of moles in 75.0 g of nitrogen gas. 14.36 g

37  How much is ONE mole of ◦ Zinc ◦ Water (H 2 O) ◦ NaCl ◦ Chromium ◦ Magnesium ◦ Sodium Bicarbonate ◦ Hydrogen peroxide ◦ carbon

38  Mole song Mole song  Boseman:  https://www.youtube.com/watch?v=Pft2CASl 0M0 https://www.youtube.com/watch?v=Pft2CASl 0M0  https://www.youtube.com/watch?v=xPdqEX_ WMjo https://www.youtube.com/watch?v=xPdqEX_ WMjo

39 Mass g Mole # of Particles (atoms, molecules) Pg 84 Use to convert between mole and mass and amount of particles 1 mol = 6.022x10 23 particles molar mass (g) = 1 mol

40 1. How many molecules are in 1.14 moles of SO 3 ? (6.87 x 10 23 atoms) 1. Calculate the mass in grams of 2.50 moles of Iron (II) Hydroxide. (Who remembers how to write this formula???) (225 grams)

41 3. If you have 7.31 grams of CuSO 4, how many moles is this? ◦ (0.0458 moles) 4. How many moles are in 4.65 x 10 23 molecules of NO 2 Is this a 1 step or 2 step problem??? (0.772 moles)

42 Mass g Mole # of Particles (atoms, molecules) 1mol _ 6.022x10 23 atoms molar mass 1mole molar mass 6.022x10 23 atoms 1mole Pg 84 Use to convert between mole and mass and amount of particles

43 Mass g Mole # of Particles (atoms, molecules) Pg 84 Use to convert between mole and mass and amount of particles 1 mol = 6.022x10 23 1 mol = molar mass

44 1. Find the mass, in grams of 4.52 x 10 23 molecules of C 20 H 42 ? ◦ (212 grams) 2. Find the number of atoms in 75.0 g of dinitrogen trioxide? ◦ Molar mass = 76.0g/mol, ◦ 5.94x10 23 atoms 3. How many grams are there in 2.80 x 10 24 atoms of silicon? ◦ Don’t forget your sig.figs! ◦ 4.65x28.1g = 131g 4. How many grams is 2.7 x 10 23 molecules of Br 2 ?  71.6 = 72g

45 1. How many molecules are in 1.14 moles of SO 3 ? (6.87 x 10 23 molecules) 2. Calculate the mass in grams of 2.50 moles of Iron (II) oxide. 179.8 g 3. How many grams are there in 2.80 x 10 24 atoms of N 2 ? ◦ Don’t forget your sig.figs! ◦ 4.65x28.1g = 131g

46  Turn in warm ups and Mole worksheet!

47  How many moles are there in 2.80 x 10 24 atoms of silicon? ◦ Don’t forget your sig.figs!  How many moles is 2.7 x 10 23 molecules of Br 2 ?  NOTICE: how we calculated for atoms when talking about an element and molecules when talking about a compound? ◦ Can you calculate atoms for a compound? Could you calculate atoms of Br 2 ? ◦ YES, but that is not a single step problem… ◦ …see next slide

48  Often multiple conversion factors are needed. ◦ Like if you need to convert your age to seconds… ◦ Go from years to months to days to hours to sec. 1. How many ATOMS of propane (a covlnt cmpd!!) are in 2.12 moles of propane (C 3 H 8 )? ◦ Why can you NOT go straight from moles to atoms in this problem? 2.12 moles x = 1.28x10 24 C 3 H 8 molecules 11 atoms per molecules (1.28x10 24 ) x 11 = 1.40 x10 25 atoms

49 2. How many ATOMS of Carbon are in 2.12 moles of propane (C 3 H 8 )? 2.12 moles x = 1.28x10 24 C 3 H 8 molecules 11 atoms per molecules (1.28x10 24 ) x 11 = 1.40 x10 25 atoms 3/11 of atoms are C 3/11 (1.40 x10 25 ) = 3.84 10 24 C atoms

50 3.How many molecules are in 1.14 moles of SO 3 ? (6.87 x 10 23 molecules) 4.How many atoms are in 1.14 moles of SO 3 ? (2.75 x 10 24 atoms) 5. How many atoms are in 1.09 x 10 24 molecules of water? 6. How many atoms of hydrogen in 2,560 atoms of water? 7. How many atoms of hydrogen in 1.50 moles of water?

51 1. What is the molar mass of 1 mole of lithium? 2. What is the molar mass of 1 mole of carbon dioxide? 3. What is molar mass of 35 grams of.5 mole of aluminum? 4. What is the molar mass of 10 moles of sodium that has a mass of 220 grams.

52 1. How many moles are in 32.58 g of H 2 O? 2. How many molecules are in 1.808 moles of H 2 O? 3. How many atoms are in 1.09 x 10 24 molecules of water? 4. What is the mass in grams of 7.23 x 10 23 molecules of sucrose (C 12 H 22 O 11 )?

53 1. How many atoms of oxygen in 3.00 moles of carbon dioxide? 2. How many atoms of hydrogen in 20.0 grams of H 4 CO

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55 The MOLE Mass (g) Molecules, atoms, formula units Volume (L)

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57 Mass g Mole # of Particles (atoms, molecules) 1mol _ 6.022x10 23 atoms molar mass 1mole molar mass 6.022x10 23 atoms 1mole Pg 84 22.4 L 1 mole Volume L 1 mole 22.4 L

58 Mass g Mole # of Particles (atoms, molecules) Pg 84 1 mol = 6.022x10 23 1 mol = molar mass Volume L 22.4 L = 1 mole

59  For gases, Avogadro (in 1811) proposed a significant relationship that stated that: equal volumes of gases at the same temperature and pressure contain equal numbers of particles. ◦ Particle size varies for different gases but because particles are so spread out, they do not take up any greater amount of space.  Temp has an effect on volume ◦ As temp. increases, volume increases  Pressure also has an effect on volume ◦ As pressure increases, volume decreases  STP = Standard Temperature and Pressure ◦ Temp = 0 degrees C & pressure = 1 atm

60  One mole of ANY gas will expand to have a volume of 22.4 L at STP.  STP = Standard Temperature and Pressure ◦ Standard Temp: 0 degrees C ◦ Standard Pressure: 1 atm MOLAR VOLUME = 22.4 L/mol (the volume of one mole of a gas)

61  The conversion factors (always): 1. How many moles of N 2 are in 120 L of gas? 120L x 1mol 22.4L = 5.36 mol N 2 Can you then calculate the mass?

62 Mass g Mole # of Particles (atoms, molecules) Pg 84 1 mol = 6.022x10 23 1 mol = molar mass Volume L 22.4 L = 1 mole

63 2. What is the volume of 2.54 moles of methane gas? ◦ 56.9L 3. How many moles are in 6.00 L of H 2 gas?.268mol.3mol 4. How many grams are in 12 L of O 2 gas? 17.1g= 17g 5. How many L of oxygen gas (at STP) are in 6.5 x 10 24 molecules of oxygen gas? 242L = 240 L

64 6. The density of a gas at STP is 0.901 g/L. What is the molar mass of the gas? 7. What gas is it? neon 8. What is the density of 1.00 mole of helium gas? 0.901 x g 22.4 L L 1 mole = 20.2 g/mol Density= mass/ volume or D= g/L 4.00 g/mol x 1mol/22.4 L =.179 g/L

65  Follow the road map!  Moles  L or L  moles: molar volume  Moles  g or g  moles: molar mass

66  0.6 moles of SO 2 is produced when coal is burned. How many liters of gas at STP is this?  At STP, what volume does 1.25 moles of He occupy?  74.5 liters of CO 2 at STP is contained in a flask. How many moles is this?  The density of a gas at STP is 1.964 g/L. What is the molar mass of the gas?  What is the density of krypton gas at STP?

67 In your Chemistry Notebook, classwork sections: Create your own molar road map including pictures and conversation factors. Be creative and use color. Include the following:  Title  Moles (in the middle)  Particles  Mass  Volume  Arrows between each unit (3 total)  Conversion factors between each unit (3 total)  A picture to represent each unit (4 total)  Color for emphasis

68  End day

69 1. At STP, what volume does 1.75 moles of He occupy? 2. What would be the volume of 8.00g of helium of STP? 3. What is the density of He at STP? 39.2L 44.8L 4.0g/mol x 1mol/22.4L =.179g/L

70  The recipe of chemistry

71 71  Suppose you are preparing a cake. Each Cake (Ck) requires 1.0 cake mix (Cm), 0.5 cup of oil (Oi), 1.0 cup of water (Wa) and 2.0 eggs (Eg).  Write the balanced equation for making:  1 ________ + 0.5 ________ + 1________ 2 _______  1 ________  1.0 cake mix + 0.5 cups oil + 1.0 cup water + 2 eggs  1.0 cake  How much is left over?

72  Calculate the number of cakes (Ck) that can be made from 12 cake mixes (Cm) ◦ 12Cm x 1 Ck = 12 Ck 1 Cm  Calculate the number of cakes (Ck) that can be made from 10.0 cups of oil (Oi) ◦ 10.0 Oi x 1 Ck = 20 Ck 0.5Oi  If you need to make 29 cakes (Ck), how many eggs (Eg) do you need? ◦ 29 Ck x 2 Eg = 58 Eg 1 Ck 1.0 cake mix + 0.5 cups oil + 1.0 cup water + 2 eggs  1.0 cake

73  Equations are a chemist’s recipe. ◦ Eqs tell chemists what amounts of reactants to mix and what amounts of products to expect.  When you know the quantity of one substance in a rxn, you can calculate the quantity of any other substance consumed or created in the rxn. Stoichiometry: the calculation of quantities in chemical reactions

74  Nearly everything we use is manufactured from chemicals. ◦ Soaps, shampoos, conditioners, CD’s, cosmetics, medications, clothes.  For a manufacturer to make a profit the chemical processes carried out in industry must be economical  A balanced equation is needed and used so chemicals are not wasted when making products

75  How would you read: ◦ N 2 (g) + H 2 (g)  NH 3 (g)  Balance and read: ◦ N 2 (g) + 3 H 2 (g)  2 NH 3 (g) ◦ Coefficients can represent different possible units  Atoms/molecules  Moles  Mass in grams  Mass of reactants equals mass of products  Law of Conservation of mass  Liters (if compound is a gas at STP)

76 1 mol N 2 +3 mol N 2  2 mol NH 3 28.0 g N 2 +3 (2.0 g H 2 )  2 (17.0 g NH 3 ) 34.0 g reactants  34.0 g products +  22.4 L N 2 67.2 L H 2  44.8 L NH 3 22.4 L N2N2 +3H 2  2NH 3

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78 ◦ What are the possible mole ratios in: N 2 (g) + 3H 2 (g)  2NH 3 (g) ◦ 1 mole of N 2 reacts with 3 moles of H 2 to produce 2 moles of NH 3. ◦ Possible mole ratios for this formula: 1N 2 1N 2 3H 2 3H 2 2NH 3 2NH 3  Reaction to form ammonia in this 1:3:2 ratio.  Mole ratios are CONVERSION FACTORS!  Once you have the ratios, you can perform calcs. (a.k.a. STOICHIOMETRY)

79 Amount of given (mol) Amount of unkown (mol) Mole unknown Mole given X = Mole ratio: from balanced equation Ex: How many moles of water are produced from 5.80 moles of oxygen gas? O 2 + H 2  H 2 O 1.Write equation 2.Balance! 3.Set up conversion factor O 2 + 2H 2  2 H 2 O 5.80mole O 2 x 2 mol H 2 O 1 mol O 2 11.6 moles water

80 1. How many moles of ammonia are produced from 0.60 moles of N 2 ? ◦ (1.2 mol NH 3 ) 2. How many moles of H 2 are needed to react with 0.43 moles of N 2 gas? ◦ (1.29 mol H 2 ) 3. How many moles of H 2 are needed to produce 1.98 moles of ammonia (NH 3 )? ◦ (2.97 mol H 2 )

81 Amount of given (mol) Amount of unkown (mol) Mole unknown Mole given X = Mole ratio: from balanced equation 5. The decomposition of potassium chlorate, KClO 3 into potassium chloride and oxygen gas is used as a source of oxygen in the lab. How many moles of potassium chlorate are needed to produce 15 mol of oxygen gas? 10 mol KClO 3 4. Ammonia, NH 3 is a widely used fertilizer and used in household cleaners. How many moles of ammonia are produced when 6 mol of H gas react with excess nitrogen gas? 4 mol NH 3 1.Write equation 2.Balance! 3.Set up conversion factor

82 Historical Chemistry: pg 303, #1-2

83  End day

84 Sn + 2HF  SnF 2 + H 2 1. How many moles of SnF 2 will be produced by 12.5 moles of HF? 1. How many moles HF are needed to produce 6.85 moles of SnF 2 ?

85  No lab balance measures moles directly, instead grams is a more practical unit.  To calculate grams: 1. convert to moles first, then grams ◦ Using our same example, you can calculate how many grams of each compound: N 2 (g) + 3H 2 (g)  2NH 3 (g)  REMEMBER: when you use a gram/mole conversion factor: 1 mol = molar mass 3.00 g N 2 x x x 1 mol 28g 2 mol NH 3 1 mol N 2 17 g 1 mol

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87 Ex 1: What mass, in grams, of glucose is produced when 3.00 mol of water reacts with excess carbon dioxide to produce glucose and oxygen? 1.Write equation 2.Balance! 3.Set up conversation factor 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 3.00mol x x 1 mol glucose 180.2g 6 mol water 1 mole 90.1g glucose Particle A Mass A Volume A Particle B Mass B Volume B Mole A Mole B 6.022x10 23 Molar Mass 22.4 L Mole Ratio

88 2. What mass of carbon dioxide is needed to react with 3.00 mol water? 2. How many moles of H 2 O are formed from a reaction using 824g NH 3 is the reaction: NH 3 + O 2  NO + H 2 O (unbalanced) 4NH 3 + 5O 2  4NO + 6H 2 O 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 132g CO 2 72.5 mol H 2 O Particle A Mass A Volume A Particle B Mass B Volume B Mole A Mole B 6.022x10 23 Molar Mass 22.4 L Mole Ratio

89 Ex 4: How many grams of SnF 2 are produced from the reaction of 30.00g HF with Sn. Sn (s) + 2HF (g)  SnF 2(s) +H 2(g) 30.00g HF x x x 5. How many grams of NH 4 NO 3 are required to produce 33.0g N 2 O? (the laughing gas needed for an anesthetic in dentistry) NH 4 NO 3(s)  N 2 O (g) + 2H 2 O (l) Particle A Mass A Volume A Particle B Mass B Volume B Mole A Mole B 6.022x10 23 Molar Mass 22.4 L Mole Ratio 1 mol HF 20.0 g HF 1 mol SnF 2 2 mol HF 156.7g SnF 2 1 mol SnF 2 117.5g SnF 2 60.0g NH 4 NO 3 6. How many molecules of oxygen gas are produced when 29.2 g of water is decomposed? (4.88 * 10 23 molecules of O 2 )

90 1. Carbon dioxide is produced from the synthesis of oxygen gas with carbon monoxide. Write and balance this chemical equation and then tell how many liters of oxygen gas are required to burn 3.86 liters of carbon monoxide. Assume STP. ◦ (1.93 L O 2 ) 2. How many grams of NH 4 NO 3 are required to produce 33.0g N 2 O? (the laughing gas needed for an anesthetic in dentistry) NH 4 NO 3(s)  N 2 O (g) + 2H 2 O (l) 3. How much water in grams is produced in this reaction? 60.0g NH 4 NO 3 27.0g H 2 O

91 Answer in classwork section of notebook: N 2 (g) + 3H 2 (g)  2NH 3 (g) 1. Calculate the number of grams of ammonia produced by the reaction of 5.40 g of H 2 with N 2. (30.6 g NH 3 ) 2. Calculate the number of liters of N 2 needed in order to react with 0.78 moles of H 2. (5.8 L N 2 ) 3. Calculate the grams of N 2 needed in order to produce 9.23 x 10 23 molecules of NH 3. (21.5 g N 2 ) Particle A Mass A Volume A Particle B Mass B Volume B Mole A Mole B 6.022x10 23 Molar Mass 22.4 L Mole Ratio

92 Answer in classwork section of notebook: N 2 (g) + 3H 2 (g)  2NH 3 (g) 1. Calculate the number of grams of ammonia produced by the reaction of 5.40 g of H 2 with N 2. (30.6 g NH 3 ) 2. Calculate the number of liters of N 2 needed in order to react with 0.78 moles of H 2. (5.82 L N 2 ) 3. Calculate the grams of N 2 needed in order to produce 9.23 x 10 23 molecules of NH 3. ◦ (21.5 g N 2 ) Ch 9.2: Answer #2-4 on page 311

93  You will ALWAYS use the new MOLE-MOLE ratio step to get you from where you are to where you are are going. Particle A Mass A Volume A Particle B Mass B Volume B Mole A Mole B 6.022x10 23 Molar Mass 22.4 L Mole Ratio

94  Carbon dioxide is produced from the synthesis of oxygen gas with carbon monoxide. Write and balance this chemical equation and then tell how many liters of oxygen gas are required to burn 3.86 liters of carbon monoxide. Assume STP. ◦ (1.93 L O 2 )

95  Aluminum reacts with oxygen to produce Aluminum Oxide. How many moles of aluminum are needed to form 3.7 moles of Aluminum Oxide? Write the balanced equation and solve. ◦ (7.4 mol Al)

96  How many molecules of oxygen gas are produced when 29.2 g of water is decomposed? The balanced chemical equation is given for you. Use your new mole map to solve. 2 H 2 O –electricity  2 H 2 + O 2 ◦ (4.88 * 10 23 molecules of O 2 )  How many molecules of oxygen are produced by the decomposition of 6.54 g of Potassium Chlorate? The balanced chemical equation is given for you. Use your new mole map to solve. 2 KClO 3  2 KCl + 3 O 2 ◦ (4.82 * 10 22 molecules of O 2 )

97  Sodium hydroxide reacts with Sulfuric acid to produce water and Sodium Sulfate. Calculate the amount of water (in grams) that would be produced from 40.87 g of the acid. ◦ (15.0 g H 2 O)  In a combustion reaction, C 2 H 4 reacts with oxygen to produce H 2 O and CO 2 in the following reaction. Balance it and then determine the amount of oxygen (in grams) that is consumed if 2.69g of water is produced. ◦ _____C 2 H 4 + _____O 2  _____CO 2 + _____H 2 O  (7.17 g O 2 )

98 Amount of given (mol) Mole unknown molar mass unknown(g) Mole given1 mole unkown Mole ratio: (balanced equation) mass of unkown (g) X x = Molar mas: (periodic table) Mass of given (g) 1 mole given mol unknown molar mass mol given given (g) Mole ratio: (balanced equation) Amount unkown (mol) X x = Molar mas: (periodic table)

99 mass of unknown (g) Mass of given (g) X x X = 1 mole given mol unknown mole mass molar mass mol given 1 mol given (g) unknown

100  End day

101 1. Carbon dioxide is produced from the synthesis of oxygen gas with carbon monoxide. Write and balance this chemical equation and then tell how many liters of oxygen gas are required to burn 3.86 liters of carbon monoxide. Assume STP. ◦ (1.93 L O 2 ) Particle A Mass A Volume A Particle B Mass B Volume B Mole A Mole B 6.022x10 23 Molar Mass 22.4 L Mole Ratio

102  The difference in the optimal, expected outcome and the actual tested outcome Experimentation is not perfect Not all reactant are react so some may be left over Conditions may not be perfect for a full reaction

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105  Limiting reagent: reactant that determines the amount of product that can be produced. ◦ It limited…  Excess reagent: reactant that is not used up in the reaction - there is more available than needed  Steps to determine LR  Calculate theoretical yield (g or mol)  Determine limited reagent  Use the original actual yield of the limiting reactant to calculate product produced (in moles or grams)

106 Flask123456 Volume acetic acid (mL) 25ml Sodium bicarbon ate (g) 0.50g1.00g1.50g2.00g2.50g3.00g Which system will produce the most CO 2 product?

107 Ex 1. Given the following balanced equation, determine which is the LR if 2.70 moles of C 2 H 4 is reacted with 6.30 moles of O 2.  C 2 H 4 + 3 O 2  2 H 2 O + 2 CO 2 ◦ (O 2 is LR) 2. Using the info gathered from above, calculate the GRAMS of water that will be produced. 75.6 g H 2 O 2.70 mol C 2 H 4 x = 5.4 mol H 2 O 2 mole H 2 O 1 mole C 2 H 4 6.30 mol O 2 x = 4.20 mol H 2 O 2 mole H 2 O 3 mole O 2 Less= limiting reagent=O 2 4.20mol x 18g/mol =

108 3. Identify the LR when 6.00 g HCl reacts with 5.00 g Mg in the following reaction:  Mg + 2HCl  MgCl 2 + H 2  (HCl is LR) 4. Using the info gathered from above, calculate the GRAMS of hydrogen gas that will be produced. ◦ (0.164 g H 2 )

109  % yield = ____actual yield___ x 100 theoretical yield  measure of the efficiency of a reaction carried out in lab.  Actual yield would be given in problem or determined from actually performing the lab.  Theoretical yield can be calculated using the Limiting Reagent.

110  If 15.0 g of nitrogen gas reacts with 15.0 g of hydrogen gas, 10.5 g of ammonia (NH 3 ) is produced. Calculate the percent yield. ◦ N 2 yields 1.07 mol NH 2 ◦ H 2 yields 5.0mol NH 2 ◦ Limiting reactant: N 2 ◦ (theoretical yield: 18.2 g NH 3 ) ◦ (percent yield: 57.7%) % yield = ____actual yield___ x 100 theoretical yield 1.Balance chemical equation 2.Find limiting reactant 3.Calculate theoretical yield 4.Find percent yield

111

112  Calculate the number of moles in 9.023 x 10 23 molecules of NO 2. (6.48 moles)  Calculate the volume of 2.30 moles of SO 2 gas at STP. (51.5 L)  Find the molar mass of B 2 (SO 3 ) 3. 261.9 g/mol

113  HS-PS1-7.Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.  HS-PS1-6.Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.  HS-PS1-5.Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.  HS-PS1-3.Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles.

114  HS-PS1-7.Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction. CA State Standards  D2. Investigate quantitative relationships in chemical reactions, and solve related problems;  D3. Demonstrate an understanding of the mole concept and its significance to the quantitative analysis of chemical reactions.

115  HS-PS1-6.Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.

116  HS-PS1-5.Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.

117  HS-PS1-3.Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles.


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