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Unit 6 Mole and Stioch.
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Unit 6 Starts Tues: Panther Drill Review Problem 5-10 min Review Quiz Early Finish = Word Search
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Panther Drill Potassium Chlorate reacts to form Potassium chloride and oxygen gas. Write the equation for this reaction, balance it, and state what type of reaction it is. Skeleton Equation:KClO 3 KCl + O 2 Balanced ____KClO 3 ___ KCl + ____O 2 323
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Wednesday PD= Converions Modeling: How to us Dim Anaylisis Practice
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TODAY Today: We will practice using dimensional analysis to convert between units. This is a review of what we did in
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Panther Drill Convert 5 feet into cm. 1 inch = 2.54 cm Set up the conversions using dimensional analysis. 5ft x 12 in2.54 cm = 1 ft 1 in 152.4 cm
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Active Inspire Practice
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Thurs Panther Drill Guess how many activity Pairs will list ways items are quantified other than by the each. Notes Discussion on the mole Exit ticket “Explain the mole is similar to a dozen.”
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Panther Drill There are 50 paperclips in a box and 20 boxes in a case. If I have 2750 paper clips how many cases do I have? TODAY 1.1 more dimensional analysis problem 2.Explain how to count large numbers of small items w/out counting them individually 3.Meet the Mole.
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Get with your partner Make a list of different units there are to count items. EXAMPLES Ream: 500 pieces of paper. A gross: A gross of something = 144 of an item Hint: How are things sold in the supermarket.
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Active inspire List our lists
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1 Intro We have seen how much easier it is to count small items such as paper clips by a larger unit rather than by the each. That was easy compared to if you had to count the number of atoms of aluminum in a paper clip.
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2 Intro Chemist often have to find out how many atoms or particles of an element or compound are in a sample. This would be nearly impossible with out a unit that would count a very small things w/ out counting each particle individually. Chemists use the Mole NO not either of these
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3 IMPORTANT!! A mole or (mol) is the SI or scientific unit for counting particles, atoms, or molecules. The mole was defined in 1811 by an Italian scientist and lawyer named Avogadro. He figured out that there was 602,213,670,000,000,000,000,000 particles of anything in 1 mole of that item. We use scientific notation = 6.02x 10 23 This is called Avogadro’s number
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4 Look at the test tubes being past around you will see that you can have moles of different kinds of particles. Tube 1 has 1 mole of copper atoms Tube 2 has 1 mole of water molecules Tube 3 has 1 mole of salt molecules Beaker has 1 mole of sugar molecules What do you notice about the moles of the items, how are they different?
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5 Think about it this way A mole of sugar molecules can look larger than a mole of salt molecules (even though they both contain 6.02x 10 23 particles) because the molecules of sugar are larger than a salt molecules. Just like a dozen marbles looks larger than a dozen than a dozen pennies, but the each have 12 items in them.
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EXIT TICKET Explain the mole is similar to a dozen. NAME:
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Monday
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Panther Drill In your own words define a mole as it is used in chemistry.
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What’s in a Mole Remember the mole is the # of particles in a sample. Avogadro's # says there are 6.02 x 10 23 particles of any thing in a mole of a sample being measures There are 3 different representative particles that a mole can count: Atoms, Molecules, and Formula units
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In an element (H,Cl, Zn ect) it represents atoms In a molecular compound such as water, sucrose, and carbon dioxide, the mole counts molecules. In an Ionic Compound like NaCl, or Magnesium Oxide, the mole counts formula units
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What is the representative particle in the following? 1.LiCl 2.C 12 H 22 O 11 3.BeH 2 4.Mg 5.PCl 5 ATOMS Formula Units Molecules
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Conversion Cheat Sheet On the index card provided or somewhere you won’t lose it write down the following: You can use this when doing conversions
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Side 2 of Index Card # of Moles = # of particles X ___1 mole __. 6.02 X 10 23 particles Finding the number of moles
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Finding the number of particles # of Particles = # moles X 6.02 X 10 23 particles 1 mole Side 1 of Index Card
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Panther Drill What is the representative particle being counted by the following: 1.NaCl 2.CO 2 3.Fe 4.H 2 SO 4
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Conversion moles to particles Convert 3.50 moles of Sucrose to # of particles 3.50 moles x X 6.02 X 10 23 particles = 1 mole DO THE MATH: 2.11 x 10 24
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Conversion (Particles to Moles) Convert 4.5 x 10 24 atoms of Iron to moles of iron What Conversion factor? # of Moles = # of particles X 1 mole ___. 6.02 X 10 23 particles Moles = 4.5 x 10 24 atoms X 1 mole ___. 6.02 X 10 23 atoms DO THE MATH: 7.48 moles Fe
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You practice now You and your partner practice now Partner A 1.2.5 moles of Zn to # atoms 2.2.9 x 10 24 formula units of NaCl to moles Partner B 1.4.0 moles of CO 2 to # molecules 2.7.2 x 10 23 formula units of Li 2 S to moles
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Tuesday
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Panther Drill 1)Convert 3.50 moles of Salt to # of particles 2)Which types of particles are you counting (atoms, molecules or formula units) in the compound salt?
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Work on some mole conversions on your own Get a WS and complete all 5 problems
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Examples Moles = 4.5 x 10 24 atoms X 1 mole _ = 7.48 moles Fe 6.02 X 10 23 atoms # Particles: 3.50 moles X 6.02 X 10 23 part. = 1 mole 2.11 x 10 24 molecules
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Use the back to do the work How many particles are in the following: a)11.5 moles of Ag______________ b)18 moles of Water_____________ c)3.9 x10 24 particles of NaCl______________ d)1.35 x 10 24 particles CH 4 ________________ e)Arrange these 3 samples in order from largest to smallest 1.25X10 25 atoms of zinc, 3.56 mole of Fe and 6.78 x 10 26 molecules of glucose.____________________________ ___________________________________
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Use the back to do the work How many particles or moles are in the following: a)11.5 moles of Ag______________ b)18 moles of Water_____________ c)3.9 x10 24 particles of NaCl______________ d)1.35 x 10 24 particles CH 4 ________________ e)Arrange these 3 samples in order from largest to smallest in terms of # of particles 1.25X10 25 atoms of zinc, 3.56 mole of Fe and 6.78 10 26 molecules glucose._______________________ ___________________________________
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Use the back to do the work How many particles or moles are in the following: 11.5 moles of Ag______________ 18 moles of Water_____________
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Use the back to do the work How many particles or moles are in the following: a)3.9 x10 24 particles of NaCl______________ a)1.35 x 10 24 particles CH 4 ________________
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Use the back to do the work How many particles or moles are in the following: Arrange these 3 samples in order from largest to smallest in terms of # of particles 1.25X10 25 atoms of zinc, 3.56 mole of Fe and 6.78 10 26 molecules glucose._______________________ ___________________________________
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Moles and Mass
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Panther Drill If 1 dozen eggs weighs 2.3 pounds, determine how much 5.5 dozen weigh. 5.5 doz 1 2.3 lb 1 doz X 5.5 X 2.3 lbs = 12.65 lbs =
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Mass and the mole in single elements A mole always contains the same number of particles; but moles of different substances have different masses. Think about it like this: A mole is like a dozen. A dozen bowling balls would have a different mass than a dozen eggs, but each one still has 12 items in it.
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Lets look at the element Carbon 1 mole of Carbon = 6.02 x 10 23 atoms Carbon has an molar (atomic)mass of 12.01 g The mass of 1 mole of a substance = the molar mass ** The mass of 1 mole of an element can be found on the periodic table 12 C Carbon 12.01
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Converting from # of moles to mass Lets look at a dozen jellybeans 1 dozen jellybeans = 35 grams THIS BECOMES OUR CONVERSION FACTOR How many grams are there in 5 dozen jelly beans? 1 dz jelly beans 5 dz Jellybeans 35 grams = __________ g 175
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Converting From Moles to Mass The mass of 1 mole of carbon = 12.01 g How many grams are there in 8 moles of carbon? 12.01 g C 8 moles of C x 1 mol C =____________ g Cu 96.08
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Moles to Mass (2) The mass of 1 mole of copper = 63.546 g How many grams in 4 moles of copper: 4 mol Cu = =____________ g Cu 1 mol Cu 262.18 65.546 g Cu
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Converting Mass to Moles You have 7.6 Grams of Boron (Atomic/Molar Mass 10.81) Convert grams of Boron to moles of Boron Conversion factor: 1 mole of boron = 10.81 grams How would you set up the conversion fraction? 7.6 g B X 1 1 mol B 10.81 g B = ________mol B 0.703
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You Try Partner A and B PARTNER A How many moles are in 15 grams of lithium? Partner B How many grams are in 2.4 moles of sulfur? Each student do their own problem and then explain how they got the answer to their partner
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Partner A How many moles are in 15 grams of lithium? (molar mass of lithium is 6.94 g/mole) 15 grams Li x 2.16 moles 1 mole = 6.94 grams 15/7 moles Li
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Partner B How many grams are in 2.4 moles of sulfur? molar mass of sulfur is 32 g/ mole 2.4 moles x 32.065 grams S 1mole S 76.956 g S
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Practice Moles to Grams of Atoms How many moles are in 22 grams of argon? How many grams are in 88.1 moles of magnesium? How many moles are in 2.3 grams of phosphorus? How many grams are in 11.9 moles of chromium? How many moles are in 9.8 grams of calcium?
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Practice Moles to Grams of Atoms How many moles are in 22 grams of argon? How many grams are in 88.1 moles of magnesium? How many moles are in 2.3 grams of phosphorus? How many grams are in 11.9 moles of chromium? How many moles are in 9.8 grams of calcium?
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MONDAY
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Panther Drill How many moles are in 198.6 grams of potassium? 198.6g K x How many grams are in 12.3 moles of nitrogen? 12.3 mol N 1mol. 39.1 g K ___________ moles K 14.01 g N 1 mol N ___________ g N 5.08 172.32
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Converting Grams to Moles to Particles 2 ways to do this 1.Convert from grams to moles then separately convert from moles to particles. Example: Convert 41.7 grams of boron to atoms of Boron a)41.7 g B = __________ mole B b)3.86 mol B =_________ atoms B 1 mole B 10.81 g B x 3.86 6.02 x 10 23 atoms B 1 mole B x 2.32x 10 24
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2. Do all the conversions in the same equation Example: Convert 41.7 grams of boron to atoms of Boron a)41.7 g B =_________ atoms B Converting Grams to Moles to Particles 1 mole B 10.81 g B xx 6.02 x 10 23 atoms B 1 mole B = # atoms B 41.7 x 6.02x10 23 10.81 2.32x 10 24
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Try This One How many atoms are in 2.13 grams of Helium INSERT ACTIVE- INSPIRE HERE
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Vitamin Lab Activity You need to get your partner assignments You need to get a lab sheet for your groups and get the material on the lab sheet. Get to work
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Tuesday Continue lab activity and turn in at the end of the period.
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Panther Drill Create a simple flow chart that shows the process of converting mass to moles, to atoms of an element. For each step, make sure to show the conversion fractions you would use to do that step Examples of flow chart outline
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Continue w/ Vitamin lab activity
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Micrograms to grams 2mcg Mg x 1 gram 1,000,000 mcg
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Wednesday P-drill Finish Vitamin Lab and turn in at end of the period. Students finishing early will do extra credit assignment converting grams to moles. Exit ticket thumbs up down on grams-moles- particle converting of an element
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Panther Drill (Review Material) 1.Which of the following elements has three valence electrons? a) lithium b) boron c) nitrogen d) more than one of the above 2.Which of the following is not an acid? a) HNO 3 b) CH 3 COOH c) H 2 SO 4 d) All of these are acids
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Thursday
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Panther Drill Find the mass of 1 mole of the following: Carbon: Phosphorus: Iron: Oxygen Gas: 12.01 30.97 55.85 From the periodic table we get 16.00 Amu, but Oxygen is diatomic so in the Real word it would be 16 x 2 = 32.00
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Formula Weight or Mass Formula Weight is the total of all the atomic masses for each element in the formula for a compound. Formula mass, Molar mass, and Formula Weight are the same thing. The formula mass or weight is like the atomic mass of a compound. The mass of 1 mole of a compound = the formula mass or weight
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Example Determine the formula mass of 1 mole of Magnesium Chloride? 1.Write the chemical formula. (if it is not given) Remember to “criss-cross” the charges to get the subscripts. (**Signs Drop off) Magnesium Chloride Mg 2+ Cl -1 2.Determine the atomic mass for each element. Mg= 24.31 g/mol ; Cl=35.45 g/mol 3.Look to see how many of each element there are in the formula. MgCl 2 Mg = 1 atom ; Cl = 2 atoms =
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Example (cont) 4.Multiply the number of atoms of each element in the formula by the atomic mass of each element. (Mg) 1 x 24.31 g = 24.31 g (Cl) 2 x 35.45 g = 70.90 g 5.Add up the results: 24.31 g + 70.90 g = 95.21 g 1 mole of MgCl 2 = 95.21 g The formula mass of MgCl 2 = 95.21 g
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70 A. 1 mole of K 2 O = ______g B. 1 mole of antacid Al(OH) 3 = ______g Learning Check How many grams in 1 mole
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71 A. 1 mole of K 2 O K: 2 x 39.1g/mol = O: 1 x 16g/mol = B. 1 mole of antacid Al(OH) 3 Al: 1 x 27.0 g/mole = O: 3x 16.0 g/mole = H: 3 x 1.01 g/mole = Solution 78.2g =94.2 g K 2 O = 78.02 g Al(OH) 3 48 16 g 78.2 + 16 3.03 27 27 + 48 + 3.03
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Practice Partner A: Molar mass of Na 3 P Molar Mass of CH 4 O 3 S (Methanesulfonic acid)Methanesulfonic acid Partner B Molar mass of AlCl 3 Molar Mass of C 6 H 12 O 6
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Calculate Molar Mass Complete the 5 problems on the 1/2 page WS and turn them in in the basket. You need to work by your self and you have 10 to 15 min to complete.
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Write the Formula Mass for the following and Turn in when completed 1.NaF 2.KGa 3.Diphosphorus trioxide 4.LiS 2 5.Diphosphorus hexachlorine 6.Al 2 O 3
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Write the Formula Mass for the following and Turn in when completed 1.NaF 2.KGa 3.Diphosphorus trioxide 4.LiS 2 5.Diphosphorus hexachlorine 6.Al 2 O 3
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76 Prozac, C 17 H 18 F 3 NO, is a widely used antidepressant that inhibits the uptake of serotonin by the brain. It has a molar mass of 1) 40.0 g/mole 2) 262 g/mole 3) 309 g/mole EXIT TICKET
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77 Prozac, C 17 H 18 F 3 NO, is a widely used antidepressant that inhibits the uptake of serotonin by the brain. It has a molar mass of 3) 309 g/mole 17C (12.0) + 18H (1.0) + 3F (19.0) + 1N (14.0) + 1 O (16.0) Solution
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Friday Students will learn to convert between grams and moles of compounds Students will work on a comprehensive work sheet that covers formula mass and converting from formula mass of a compound to moles of a compound. Individual work will take all period
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79 Prozac, C 17 H 18 F 3 NO, is a widely used antidepressant that inhibits the uptake of serotonin by the brain. It has a molar mass of___________________? Panther Drill
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80 Prozac, C 17 H 18 F 3 NO, is a widely used antidepressant that inhibits the uptake of serotonin by the brain. It has a molar mass of 17C x (12.01)= 18H (1.01) = 3F (19.0) = 1N (14.01) = + 1 O (16.0) = Solution 309.36 g/mole of Prozac 204.17 18.18 57.00 14.01 16.00 309.36
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Panther Drill Calculate the molar mass of aspirin (C 9 H 7 O 4 )
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Converting between Moles and Mass of a compound. Done the same way as w/ elements Same conversion Fractions but w/ compounds not elements and molar mass instead of atomic mass Grams x 1 mole of compound = # moles compound molar mass of compound
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1)See what the problem gives you and see what it is asking for. 2)Determine the chemical formula & calculate the molar mass 3)Do the math Mass to moles: Molar mass on the bottom of the fraction and divide. Moles to mass: molar mass on top and multiply REMEMBER WHEN GOING MASS-MOLES WE DON’T NEED 6.02 X 10 23 Converting between Moles and Mass and moles to mass of a compound.
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EXAMPLE Mass to Moles How many moles are in 198 grams of water? Step 1: See what you are given in the problem and what it wants you to answer. 198 grams H 2 O ; Wants Moles of H 2 O Step 2: Determine the chemical formula & calculate the molar mass H: 2 x 1.08 O: 1 x 16.0 Molar Mass = 18.16 g/mole of water Converting between Moles and Mass of a compound. 2.16 + 16
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Converting between Moles and Mass of a compound 3. Multiply the mass you are given by 1 mole over the molar mass of water. Then simplify, the fraction that is left (divide the top number by the bottom. 198 g divided by 18.16 g = moles water) 198 g of water x = = _______ mole Water 1 mole water 18.16 g water 10.93 198 = 18.16
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You Try How many moles are in the 171.16 grams of Lithium Chloride?
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EXAMPLE Moles to Mass What is the mass of 4.5 moles of CO 2 Step 1: See what you are given in the problem and determine the chemical formula of the compound. Step 2: Calculate the molar mass C x 1 = 1x 12.01 g O x 2 = 2 x 16 g Molar Mass = 44.01 g/mole of CO 2 Converting between Moles and Mass of a compound. 12.01 + 16 CO 2
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Moles to Mass (cont) EXAMPLE Moles to Mass Step 3: Set up the equation by multiplying the # of moles given by the molar mass over 1 mole. 4.5 moles CO 2 x = 198.0 5 mol CO 2 44.01 gramsCO 2 1 mole CO 2 = 4.5 x 44.01
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Partner A / B Partner A: You are given 5.46 moles of MgO how many grams do you have? Partner B: You need to convert 164.4 grams of CaCl 2 to moles. When you are finished explain to each other how you got your answers and sign off on each others work
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Fri
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Panther Drill Organize your materials for your open notes quiz. Ask any questions you have. Study If the class is loud we will immediately start the quiz. After you turn your quiz in to me at the desk, pick up a practicing percentages problem set. Turn in panther drill from Tuesday, and any other work still out in the basket on the table.
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Weds Mon and Tues = Sub
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Panther Drill % review 1.Mary has a monthly salary of $1200. She spends $280 per month on food. What percent of her monthly salary does she spend on food? 280/1200 x 100 = 23.33% 2.What is 98.3% of 23? 98.3%/100.983 x 23 = 22.61 No Panther Drill for Monday WEDS CLASS WILL MEET IN MEDIA CENTER
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Thursday Percent Practice
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Convert the following to fractions: 1.37% 2..983 98.3/100 37 100 Panther Drill
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Definition Percent can be defined as “of one hundred.” 100 of
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Percents Have Equivalents in Decimals and Fractions 20%.20 20 100 1515 = == DecimalFraction Simplified Percent Always simplify fraction to lowest terms!!!
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Remember These Equivalent Fractions 1 2 1 4 3 4 1 3 = = = = 50% 25% 75% 33.3% = = = = 66.6% 20% 40% 60% 2 3 1 5 2 5 3 5
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How to Find the Percent of a Whole Number The first thing to remember is “of” means multiply in mathematics. of = x
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Copyright © 2000 by Monica Yuskaitis How to Find the Percent of a Whole Number Step 1 - When you see a percent problem you know when you read “of” in the problem you multiply. 25% of 200 x
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Copyright © 2000 by Monica Yuskaitis How to Find the Percent of a Whole Number Step 2 – Change your percent to a decimal and then move it two places to the left. 25% x 200..
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How to Find the Percent of a Whole Number Step 3 – Multiply just like a regular decimal multiplication problem. 200 x. 25 50.00
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Is/of = %/100 IS = % OF 100 IS x 100 = OF x % Cross Multiple Solve for what ever is unknown
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Is/of (cont) 26 is what % of 34? Step 1) See what you are given is = 26 of = 34 % = ???? Step 2: Set up: is/of = %/100 26=X 34 100 Step 3: Isolate unknown and solve: Cross multiply: 34X = 2600 Divide to isolate unknown 34X = 2600 34 X = 76.47
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Quick Practice A/B Partner Convert these to fractions: 1)79% 2).55 3)33.3% Convert these to decimals: 1)21% 2)6/8 3)66%.21.75.66 79/100 55/100 or 11/20 33/100 Or 1/3
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Quick Practice 2 Convert these to %: 1)2/5 2)2/10 3).5934 4).026 5)1.64 40% 20% 59.34% 2.6% 164%
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Practice.
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Panther Drill Example 1. Homer has a box of assorted doughnuts. 3 of these doughnuts are chocolate. What percentage of Homer's doughnuts are chocolate? (note, we are talking about total number, not mass, in this case.)
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Solution number of chocolate doughnuts % of doughnuts that are chocolate = ------------- x 100 Total # doughnuts 3 % of doughnuts that are chocolate = ----------- x 100 12.25 x 100 = 25% Chocolate
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Percent composition As we briefly discussed in the beginning of the year, percent composition is the amount of each element in (in %) a compound. Also called mass percent of a compound. Mass % = mass of element in 1 mole of a compound X 100 molar mass of compound
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Mass % of H and O in Water What is the % composition of Oxygen in water? Molar Mass H 2 O: 18.02 g Mass of O in H 2 O: 16 g Mass% O = (16 / 18.02) X 100 Mass % O = 0.8879 X 100 Mass % O = 88.79 Oxygen accounts for 88.79% of the mass of a molecule of water
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Mass % of H and O in Water What is the % composition of Hydrogen in water? Molar Mass H 2 O: 18.02 g Mass of H in H 2 O: [2 x 1.01] = 2.02 g Mass% O = (2.02/ 18.02) X 100 Mass % O = 0.1121 X 100 Mass % O = 11.21 % Hydrogen accounts for 11.21% of the mass of a molecule of water
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Lets do a problem together What is the mass % of sodium in NaCl?
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Partner A /B Partner A: Determine the mass % of Carbon and Hydrogen in CH 4. Partner B: Determine the mass % of Phosphorus and Oxygen in PO 3 Sign off on and check your partners work
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Panther Drill Do this somewhere in your notes, I will be around to check it. What is the Mass% of each element in Sucrose: C 12 H 22 O 11
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Panther Drill 1.How does ionization energy and atomic radius change as move to the right across and down the periodic table. IE: As you move across a period, first ionization energy increases As you move down a group, first ionization energy decreases. AR: As you move down a group, atomic radius increases. As you move left to right across a period, atomic radius decreases.
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Work on Lab report DUE WEDNESDAY at the beginning of class
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Choices If you finish early, either work on the Chapter 11, pre-assignment OR use your knowledge of elements and the periodic table to complete the “Its Elementary” Chemistry March Madness assignment.
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Real Bracket
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Its Elementary Bracket Rules Round # 1.The element discovered first wins the game and moves on. 2.Ionization E the highest wins the game and moves on. 3.Element in the group w/ the highest group number wins and moves on. 4.Atomic Radius the highest wins the game and moves on.
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Its Elementary Bracket Rules Semi-finals (final 4): Solve the riddles to determine the two elements that will compete for the championship. Finals: Fill in the blank on the your insruction sheet to determine the winner
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Chap 11 Pre-Assignment Use the text book to complete the packet.
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Panther Drill 1.List 3 things that you can observe that tell you a chemical reaction or a chemical change has occurred. a.New substances are formed b.It burns (light) c.Temperature changes without adding or removing heat d.It bubbles (makes a gas) e.It changes color f.It forms a precipitate
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Parts of Chemical SO 3 (g) + H 2 O (l) ---> H 2 SO 4 (aq) ReactantsProducts Yields State of Compound
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Real World Connection SO 3 (g) + H 2 O (l) ---> H 2 SO 4 (aq) Above is the equation for acid rain This results from the release from industry and natural sources into the atmosphere. The Sulfur trioxide is mixed into the atmosphere when it rain the Sulfur trioxide mixes with rain water as it condensates from the atmosphere and falls to earth as Sulfuric acid.
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Demo Lab 1.Was this a chemical rxn? How Could you tell? 2.If the word equation is aqueous Hydrochloric acid and zinc metal mixes to produce Zinc chloride powder, water and Hydrogen gas. What is the symbol equation? 3.Now balance the equation. 4.Would there be more H gas produced if I kept adding HCl until the test tube was 80% full? Why or Why not.
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Panther Drill What “LAWs” tells us that equations must be balanced with = amounts on each side of the yield sign? Be specific. Law of Conservation of Mass (Mass doesn't change) Law of Conservation of Matter (Moles don’t change)
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STOICHIOMETRY
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What is stoichiometry? Stoichiometry is the quantitative study of reactants and products in a chemical reaction.
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Panther Drill In your own words define a ratio, and give an example.
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What You Should Expect Given : Amount of reactants Question: how much of products can be formed. Example 2 A + 2B 3C Given 20.0 grams of A and sufficient B, how many grams of C can be produced?
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What do you need? You will need to use i.molar ratios, ii.molar masses, iii.balancing and interpreting equations, and iv. conversions between grams and moles. Note: This type of problem is often called "mass-mass."
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Steps Involved in Solving Mass-Mass Stoichiometry Problems Balance the chemical equation correctly Using the molar mass of the given substance, convert the mass given to moles. Construct a molar proportion (two molar ratios set equal to each other) Using the molar mass of the unknown substance, convert the moles just calculated to mass.
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Mole Ratios A mole ratio converts moles of one compound in a balanced chemical equation into moles of another compound.
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Example Reaction between magnesium and oxygen to form magnesium oxide. ( fireworks) 2 Mg(s) + O2(g) 2 MgO(s) Mole Ratios: 2 : 1: 2
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Practice Problems 1) N 2 + 3 H 2 ---> 2 NH 3 Write the mole ratios for N 2 to H 2 and NH 3 to H 2. 2) A can of butane lighter fluid contains 1.20 moles of butane (C 4 H 10 ). Calculate the number of moles of carbon dioxide given off when this butane is burned.
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Panther Drill What is the ratio between male and female students in the picture: write all possible ratios, then write it out like a chemical equation. class picture
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Panther Drill answers 1) 17 total students, 7 females, 10 males. Males to females = 10 to 7 or 10 males 7 female Females to males: 7 to 10 or 7 females 10 males Males to total: 10 : 17 10 males/17 students Females to total 7 : 17, 7 females/17students Bal Equat: 10 males + 7 females Class
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Ratios Ratios can be expressed in many ways: 3:5, 3 to 5 or 3/5 We are going to be mainly concerned with ratios displayed as fractions The ratio of A to B = A. B **** The first item (number) always is the numerator, the last is the denominator. ***
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Ratios 1)It takes 2 eggs ¼ onion, 12 slices of jalapenos and 1 slice of cheese to make Mr P.’s favorite omelet what are the total ratio and the ratio of each ingredient to the end(fraction form) result. Total: 2eggs : ¼onion: 12jalapeno: 1slice: 1omelet 2 eggs/1omelet¼ onion/1 omelet 12 slices jalapeno/ 1 omelet 1 slice of cheese/ 1 omelet. Is this a problem a good example to use in chemistry? Why?
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Example
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Panther Drill Balance the equation and write down the ratios of each reactant to the product _____H 2 + _____O 2 _____H 2 O 2 mol H 2 : 2 mole H 2 O -- 1:1 1 mol O 2 : 2 mole H 2 O 212
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Panther Drill Balance the equations and write the mole ratios of each reactant to each product (Should be 4 ratios total) _____NH 3 + _____O 2 _____NO + _____H 2 O NH 3 /NO NH 3 / H 2 O O 2 /NO O 2 / H 2 O
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Set this chart up in notebook Steps Problem 1Problem 2 1 2 3 4 5
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Solving Mole-Mass or Mass to Mass Problems. List these in your table next to the number 1.Identify what is given and what the problem is asking for. 2.Write and balance the chemical equation correctly. (depending on what is required) ** 1 and 2 can be in either order 1.Using the molar mass of the given substance, convert the mass given to moles (if needed) 2.Construct a molar proportion equation (w/ one or more molar ratios in conversion fraction form) 3.Convert the moles just calculated to mass wanted by the problem.
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Problem If you have 13 moles of oxygen and excess Aluminum, how many grams Aluminum Oxide will be formed? 1) GIVEN:_____________ NEEDED:______________ 13 mol O 2 Grams Al 2 O 3
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2) Write and or balance the chemical equation correctly. ______Al + _____O 2 _____ Al 2 O 3 432
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3) Using the molar mass of the given substance, convert the mass given to moles (if needed) NOT NEEDED IN THIS PROBLEM BECAUSE YOU HAVE BEEN GIVEN MOLES, OFTEN YOU WILL BE GIVEN MASS OF A SUBSTANCE!!!!
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4) Construct a molar ratio equation (w/ one or more molar ratios in conversion fraction form) & do the math Mole ratio = 3 moles O 2 : 2 moles of Al 2 O 3 Keeping in mind we have oxygen and need to find Al 2 O 3, what goes in the numerator and what goes in the denominator? 2 moles of Al 2 O 3 3 moles of O 2 13 moles of O 2 X 2 moles of Al 2 O 3 3 moles of O 2 = 8.67mol Al 2 O 3
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5) Convert the moles just calculated to mass wanted by the problem (using molar mass) Atomic masses: Compound: Al 2 O 3 Molar Mass = (27 x 2) + (16 x 3) = X = 102 g per mole of Al 2 O 3 O = 16, Al = 27 8.67mol Al 2 O 3 102 g Al 2 O 3 1 mole Al 2 O 3 884.34 g Al 2 O 3
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Panther Drill List the steps to solve mass to mass problems 1 2 3 4 5
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PD answers 1.What are you given and what is needed 2.Balance equation, if not already. 3.Convert grams of the substance given in the problem to moles, if not already given moles. 4.Create a equation using a mole ratio to change given into what is needed. 5.Convert moles of the substance just solved for into grams.
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Create a table in your notes like is on the next slide
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Set this chart up in notebook Steps Problem 1Problem 2 1 2 3 4 5
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Solving Mole-Mass or Mass to Mass Problems. List these in your table next to the number 1.Identify what is given and what the problem is asking for. Have: “have, will react, are consumed…” Need: “are produced, will be made, yields…” 2.Write and balance the chemical equation correctly. (depending on what is required)
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Solving Mole-Mass or Mass to Mass Problems. List these in your table next to the number 3.Using the molar mass of the given substance, convert the mass given to moles (needed if you are given grams, not needed if given moles) 4.Construct a molar proportion equation (w/ one or more molar ratios in conversion fraction form) 3 mol N 2 / 1 mole Mg 5.Convert the moles just calculated to mass wanted by the problem.
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Problem If you have 13 moles of oxygen and excess Aluminum, how many grams Aluminum Oxide will be formed? 1) GIVEN:_____________ NEEDED:______________ 13 mol O 2 Grams Al 2 O 3
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2) Write and or balance the chemical equation correctly. ______Al + _____O 2 _____ Al 2 O 3 432
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3) Using the molar mass of the given substance, convert the mass given to moles (if needed) NOT NEEDED IN THIS PROBLEM BECAUSE YOU HAVE BEEN GIVEN MOLES, OFTEN YOU WILL BE GIVEN MASS OF A SUBSTANCE!!!!
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4) Construct a molar ratio equation (w/ one or more molar ratios in conversion fraction form) Mole ratio = 3 moles O 2 : 2 moles of Al 2 O 3 Keeping in mind we have oxygen and need to find Al 2 O 3, what goes in the numerator and what goes in the denominator? 2 moles of Al 2 O 3 3 moles of O 2 13 moles of O 2 X 2 moles of Al 2 O 3 3 moles of O 2 = 8.67mol Al 2 O 3
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5) Convert the moles just calculated to mass wanted by the problem (using molar mass) Atomic masses: Compound: Al 2 O 3 Molar Mass = (27 x 2) + (16 x 3) = X = 102 g per mole of Al 2 O 3 O = 16, Al = 27 8.67mol Al 2 O 3 102 g Al 2 O 3 1 mole Al 2 O 3 884.34 g Al 2 O 3
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Column #2 Mole-Mass Problem You Try Problem : 1.50 mol of KClO 3 decomposes. How many grams of O 2 will be produced? [k = 39, Cl = 35.5, O = 16] 2 KClO 3 2 KCl + 3 O 2
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Steps…Get Your Correct Answer Is equation balanced? What do you have, what do you need Use mole ratio Get the answer in moles Convert to grams using molar mass REMEMBER If you are given a mass in the problem, you will need to convert this to moles first. Ok? YES 1.50 mol of KClO 3 grams of O 2 3 mol O 2 / 2 mol KClO 3 O 2 = 32
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Mass reactant to Mass Products Given the reaction __Mg 3 N 2 + __H 2 O ___MgO + ___ NH 3 If 125 grams of MgO is produced, how much Mg 3 N 2 was required in the reactants. Assume you have plenty (excess) water. What are the words that tell you what you have and what you need?
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Panther Drill Complete the handout on your desk, it is eerily similar to the one we did last Thursday/Friday!!!
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A/B Partners 1.Get w/ a partner, If there is an odd # I will be a partner. 2.1 Person do problem A, 1 Person do problem B. BY YOURSELVES!!!!! 3.When both are FINISHED. Each partner will explain their problem to the other STEP BY STEP. 4.Sign off on each others work and let me see it.
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Partner A and B For the reaction 2Na + Cl 2 2NaCl, how many grams of sodium chloride can be produced from 500. g each of sodium ? For the reaction 2Na + Cl 2 2NaCl, how many grams of sodium chloride can be produced from 500. g each of chlorine ?
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Partner A and B For the reaction 2Na + Cl 2 2NaCl, how many grams of sodium chloride can be produced from 500. g each of sodium ? For the reaction 2Na + Cl 2 2NaCl, how many grams of sodium chloride can be produced from 500. g each of chlorine ?
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Partner A-B Problems A)Salt and water are react to form NaOH, Cl 2 and H 2. If 4.25 moles of salt is completely reacted, how much chlorine gas will result? __NaCl + __ H 2 O __ NaOH + __ Cl 2 + __H 2 B)Using the unbalanced equation: __CaC 2 + __H 2 O __C 2 H 2 + __Ca(OH) 2. If 234 grams of C 2 H 2 are produced, how much water will be needed in the reactants?
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Partner A-B Problems A)Salt and water are react to form NaOH, Cl 2 and H 2. If 4.25 moles of salt is completely reacted, how much chlorine gas will result? __NaCl + __ H 2 O __ NaOH + __ Cl 2 + __H 2 B)Using the unbalanced equation: __CaC 2 + __H 2 O __C 2 H 2 + __Ca(OH) 2. If 234 grams of C 2 H 2 are produced, how much water will be needed in the reactants?
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Using the unbalanced equation: __CaC 2 + __H 2 O __C 2 H 2 + __Ca(OH) 2. If 15 grams of C 2 H 2 are produced, how much water will be needed in the reactants? 1)____ Na 3 PO 4 + ____ KOH ____ NaOH + ____ K 3 PO 4 ___________________ 2)____ MgF 2 + ____ Li 2 CO 3 ____ MgCO 3 + ____ LiF___________________ 3)____ P 4 + ____ O 2 ____ P 2 O 3 _________________ 4)____ RbNO 3 + ____ BeF 2 ____ Be(NO 3 ) 2 + ____ RbF_________________ 5)____ AgNO 3 + ____ Cu ____ Cu(NO 3 ) 2 + ____ Ag_________________ 6)____ CF 4 + ____ Br 2 ____ CBr 4 + ____ F 2 _________________ 7)____ HCN + ____ CuSO 4 ____ H 2 SO 4 + ____ Cu(CN
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Panther Drill Chem 4-14 Balance these equations ____C 6 H 12 O 6 + ____O 2 ___CO 2 + ____H 2 O 1 6 6 6 ___ GaBr 3 + ___ Na 2 SO 3 ___ Ga 2 (SO 3 ) 3 + ___ NaBr 2 3 1 6
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Panther Drill 4/15 What is the % of Sodium in salt? Mass % = mass of element in 1 mole of a compound X 100 molar mass of compound % = atomic mass of sodium X 100 molar mass salt = 23 g X 100 = 58.5 g 39.32 %
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1)____ Na 3 PO 4 + ____ KOH ____ NaOH + ____ K 3 PO 4 2)____ MgF 2 + ____ Li 2 CO 3 ____ MgCO 3 + ____ LiF 3)____ P 4 + ____ O 2 ____ P 2 O 3 4)____ RbNO 3 + ____ BeF 2 ____ Be(NO 3 ) 2 + ____ RbF 5)____ AgNO 3 + ____ Cu ____ Cu(NO 3 ) 2 + ____ Ag 6)____ CF 4 + ____ Br 2 ____ CBr 4 + ____ F 2 7)____ HCN + ____ CuSO 4 ____ H 2 SO 4 + ____ Cu(CN
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Practice Determine the % composition of the following: 1.% Cl in NaCl 2.% H in C 6 H 12 O 6 3.% Al in Al 2 O 3
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Practice Determine the % composition of the following: 1.% Cl in NaCl 2.% H in C 6 H 12 O 6 3.% Al in Al 2 O 3
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