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Unit 4 cp the molef

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Class Powerpoint Unit 4

Class Powerpoint Unit 4

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Unit 4 cp the molefPresentation Transcript

• Unit 4The Mole
• Unit 4Measuring Matter
• Warm-UpIdentify terms we use everyday that describe a quantity. (at least 3)
• Warm-UpWhat is the common meaning of a mole?What is the scientific meaning of a mole?
• Do you ask for 12? Do you ask for 24?OR do you ask for a DOZEN??? Counting particles
•  Much easier for the product we are buying if it is sold in UNITS.
• The Mole is…Abbreviated molSI unit, used to measure the amount of a substanceDefined as the number of carbon atoms in exactly 12 g of pure carbon-12
• Common meaning Scientific meaningA small burrowing An SI base unit used toanimal. measure the quantity of matter.The damage to thelawn was caused by a The chemist measured out amole. mole of the compound.
• Avogadro’s Number Thenumber 6.0221367 x 10 23 Avogadro was a Italian physicist.
• Avogadro’s NumberAvogadros number is rounded to three significant figures.Is used to measure extremely small particle such as atoms.
• Converting between Molesand ParticlesSuppose you buy 3 ½ dozen of roses and you want to know how many roses you have.Example Calculation (Work problem out)Describe how you can tell if the wrongconversion factors has been used.
• Moles to particlesHow many particles arein 3.50 mol of sucrose?
• Reinforcement Problems1. Zinc (Zn) is used to form a corrosion- inhibiting surface on galvanized steel. Determine the number of Zinc atoms in 2.50 mol Zn?2. Calculate the number of molecules in 11.5 mol of water (H2O).3. Challenge Calculate the number of oxygen atom in 5.0 mol of oxygen molecules. Oxygen is a diatomic molecule O2
• Particles to Moles Youcan convert between moles and number of representative particles by multiplying the known quantity by the proper conversion factor.
• ReinforcementHow many moles are ineach of the following? a. 5.75 x 1024 atoms Al b. 2.50 x 1024 atoms Fe
• Unit 4Measuring matter worksheet
• Unit 4Mass and the Mole
• Calculate the number of molecules in 5.67 mol of water (H2O).
• Mass and the MoleAmole always contain the samenumber of particles; however, molesof different substances have differentmasses.
• Real world application  Youwould not expect a dozen limes to have the same mass as a dozen eggs. WHY?Eggs and Limes differ in size and composition. One mole quantities has different masses for the same reasons.
• Molar MassThe atomic weight of and element expressed in grams is the mass of one mole of that element. Unit g/mol
• Apply What of the mass of one mole of copper? 63.546 g
• Using molar mass-Real World Application Imagine that we buy jelly beans bulk, and sell them by the dozen. We soon realize that counting out a dozen or 10 dozen every time someone orders some is to much work, What can we do instead?
• Using molar mass- Real World Application The mass of…1 dozen Jelly Beans = 35 g of Jelly BeansConversion Factors= ??
• Using molar mass-Real World Application What mass of Jelly beans would you measure if a customer want 5 dozen jelly beans? 175 g Jelly beans
• Moles to MassSuppose you need to measure out 3.00 mol of copper (Cu).Howwould you measure that amount? 191 g Cu Suppose you want to go grams back to moles?
• Mole-to-Mass Conversion1. Determine the mass in grams of each of the following. a. 3.57 mol Al b. 42.6 mol Si2. Challenge Convert each given quantityin scientific notation to mass in gramsexpressed in scientific notation. a. 3.45 x 102 mol Co b. 2.45 x 10-2 mol Zn
• Mass-to-Mole 1. Determine the number of moles in each of the following. a. 25.5 g Ag b. 300.0 g S
• Unit 4Mass and the MoleMass-to-atoms
• Converting between mass and atoms Back to the jellybean example… at the end of the day you have 550 g of jelly beans left over, how many jelly beans is that? Remember 35 g= 1 dozen
• Steps to follow1. grams of jelly beans  dozens of jelly beans2. Dozens of jelly beans  # of jelly beans
• ReinforcementMass to atoms/ Atoms to mass Worksheet
• Unit 4Re-cap
• Activity Ona blank sheet of computer paper design a concept map, outlining the conversion between mass, moles, and particles
• Warm-UpCalculate the mass of 0.25 mol of carbon-12
• Unit 4Moles of a compound
• Chemical Formulas & The MOLE  Chemical formula=indicates the number and types of atoms contained in one unit of the compound.
• InterpretHow many of each kind of atom- carbon, chlorine, and fluorine-are contained in 1 mol of CCl2F2 ?C=1Cl=2F=2
• Interpret How many moles of F are in 5.50 of freon (CCl2F2 ) ?11.0 mol F atoms
• Molar mass of CompoundsCalculate the molar mass of K2CrO4. 194.20 g
• Reinforcement1. Determine the molar mass of each ionic compound. a. NaOH b. CaCl2 c. KC2H3O22. Calculate the molar mass of eachmolecular compound. a. C2H5OH b. HCN
• Converting Moles to mass  How many grams of F are in 11.0 mol F ?
• Conversion Factors Conversion factors map
• Unit 4Measuring matter Lab
• Warm-UpSuppose a student measured out 8.91 g of Al2O3 Aluminum oxide… (answer the following) Molar mass of Al2O3 Moles of compound Moles of each element Atoms of each element
• Warm-Up Suppose a student measured out 81.2 g of CaCO3 Calcium Carbonate… (answer the following)  Molar mass of  Moles of compound  Moles of each element  Atoms of each element
• Warm-UpSuppose a student measured out 81.2 g of CaCO3 Calcium Carbonate… (answer the following) Molar mass of Moles of compound Moles of each element
• Measuring Matter LabSafety-goggles, glovesProper use of equipmentProcedureExpectation –Clean Lab areaQuestions?
• After LabComplete analysisWork on review/homework packetStudy for Quiz
• Unit 4Chalk Lab
• Warm-UpFind the molar mass of calcium carbonate (CaCO3)
• Lab ExpectationsFindthe following… How many moles of chalk How many mole of Ca… How many atoms How many moles of C… How many atoms How many moles of O… How many atoms
• Lab ProcedureFind mass before-recordFind mass after-recordFind molar massDetermine the number of mole required
• Unit 4Mole & the volume
• Warm-UpHow much does 4.2 moles of Ca(NO3)2 weigh?
• Quiz
• Unit 4Mole & the volume
• Moles to VolumeIn the calculations, some questions should use conversions more than once; however, mole is in the center , because all conversions between mass, particles and volume should be converted to moles at first.
• Moles and volume
• Unit 4Empirical and Molecularformulas
• Real World Application You might have noticed that some food containers contain two or more serving instead of the single serving you would expect. How would you determine the total number of calories contained in the package?
• Real World Application What do you do??
• Percent by massPercent by mass: the ratio of the mass of each element to the total mass of compound expressed as a percent.
• Percent CompositionPercent by mass (element) = mass of element -------------------------- X100 = mass of compound
• Sample Problem You have a 100g sample of a compound that contain 55 g of element X and 45g of element Y. The compound is 55% X and 45% Y
• The percent composition from the Chemical FormulaPercent by mass= mass of element in 1 mol of compound -------------------------------------------------------------------- X 100 molar mass of compound
• Unit 4Empirical formula from masscomposition
• Empirical formula ISTHE FORMULA WITH THE SMALLEST WHOLE-NUMBER MOLE RATIO OF THE ELEMENTS. The empirical formula might or might not be the same as the actual molecular formula, of different the molecular formula will be a simple multiple of the empirical formula.
• Empirical formulaFor example:Hydrogen peroxideEmpirical formula= HOMolecular formula= H2O2
• How do you find empiricalformula? Percent composition or masses of the elements in a given mass of compound
• List the steps needed to calculatethe empirical formula frompercent composition data…1. Assume that the total mass of the compound is 100.00 g the percent by mass of each element is equal to the mass of each element in grams2. Convert the mass of each element to moles using the molar mass as a conversion factor.
• List the steps needed to calculatethe empirical formula frompercent composition data…3. Divide each molar amount by the smallest mole value4. If needed multiply each by an interger to determine the smallest whole-number ratio5. Write the empirical formula using the smallest whole-number ratio.
• Reinforcement Empiricalformula from percent composition Methyl acetate is a solvent commonly used in some paints, inks, and adhesives. Determine the empirical formula for methyl acetate, which has the following chemical analysis: 48.64% carbon 8.16% hydrogen 43.20% Oxygen
• 1. Assume that each percent by mass represents the mass of the element in 100g sample, the percent sign CAN BE REPLACED WITH GRAMs(g).2. Convert each mass to moles using conversion factors (inverse molar mass- that relates moles to grams)3. Calculate the simplest ratio of moles of elements by dividing the moles of each element by the SMALLEST value in the calculated mole ratio.4. Multiply each number in the ratio by the SMALLEST number
• Reinforcement Empiricalformula from percent composition Methyl acetate is a solvent commonly used in some paints, inks, and adhesives. Determine the empirical formula for methyl acetate, which has the following chemical analysis: 48.64% carbon 8.16% hydrogen 43.20% Oxygen
• Unit 4Molecular formula
• Molecular formula Specifiesthe actual number of atoms of each element in one molecular formula unit of the substance