Stoichiometry - Principles of Chemistry I - Lecture Slides, Slides of Chemistry

Download Stoichiometry - Principles of Chemistry I - Lecture Slides and more Slides Chemistry in PDF only on Docsity! Chemical Stoichiometry Mole Concept Reactants & Products Limiting Reagents Percentage Yield Calculations Chemical Equations Percent Composition Avogadro's Number Atomic & Molecular Weights Mass Measurements Positive-ion-beam detector positive Sample ions Separation of ions based on Ionizing To vacuum mass differences electron pump beam • Lavoisier: mass is conserved in a chemical reaction. • Chemical equations: descriptions of chemical reactions. • Two parts to an equation: reactants and products: 2H2 + O2  2H2O Chemical Equations One methane , Two oxygen One carbon Two water —> *. molecule molecules dioxide molecule molecules oO . CH, + (in) 40) (3) Mole Concept with Balanced Equation Periodic Table of the Elements 3 3 © Alkali Metals El Gaseous State Alkaline Earth Metals El Liquid State lA Trenetion Mele Sold tte IA IVA VA VIA VIIA 4 Other Metals &| Synthetically Prepared / fe | & Mi Nonmetals ‘ Bi | “vam Wi Nnoble Gases see ® Inner Transition Metals <a ye 1B IVB VB VIB VIIBr——VIIB— 1B iI 543 false Se di LY, 1G aie eo, Cu | st, i SY Zr Nb Mo i Ru Rh Pa A i CREM eC TERE ee lee _ ere Taar s7a4o seo saa A002 11902 we REL, 149509 19687 200 204.37 2072 208.98 Bi, Po | *Name Not Officially Assigned iS i a a Lanthanse Series +Lall Gel Pr Nd) al Sr $m Eu Gd Th Dy Ho Er Tm Yb 138.91 140.12 140.91 144.24 fda, 150.4 151.96 15725 158.93 ‘So a ie Bk Tee setnise sores AG) THE Pal Ul iio pul aa) Gal Be CP es) Fal wie lo (227) 232.04 231.04 238.03 237.05 (244) (243) (247) (247) (251) (254) (257) (258) (259) The Mole 1 amu = 1.66054 x 10-24 g 1 g = 6.02214 x 1023 amu The Mole This photograph shows one mole of solid (NaCl), liquid (H2O), and gas (N2). CyberChem: Mole The Mole Acronym Meaning Units Conversion Factors AW Atomic Weight g mol-1 g atoms = mol atoms MW Molecular Weight g mol-1 g molecules = mol molecules L Avogadro’s # (6.022x1023 mol-1) (#) mol-1 # atoms/molecules = mol atoms/molecules Formula (mol) ratios of atoms in molecule Balanced Equation mol ratios of species in reaction Percentage Composition from Formulas • Percent composition is the atomic weight for each element divided by the formula weight of the compound multiplied by 100: Formula Weights    100 Compound ofFW AWElement of Atoms Element %  Calculations with Balanced Equations Stoichiometric Coeff’s - Moles - Quantitative • Look for Balanced Chemical Equation • Focus onto Species concerned • Convert to Moles of Species • Convert to Equivalent Moles of Species in Question • Convert to Desired Units • Use the Factor Label Method C3H8(g) + 5 O2(g)  3 CO2(g) + 4 H2O() MW(g/mol): 44.11 32.00 44.01 18.02 C3H8(g) + 5 O2(g)  3 CO2(g) + 4 H2O() MW(g/mol): 44.11 32.00 44.01 18.02 22.7 g H2O Given 50.3 grams of each reactant: which reactant in excess? how many grams of water produced? Percents to Formula Percent Nitrogen Hydrogen Relative Mass (relative to 100 grams) Relative Moles (divide by respective AW) Simplest Atom/Mole Ratio (divide by smallest mole) Simplest Integer Ratio At room temperature and pressure, sodium is dissolved in water to give sodium hydroxide and hydrogen. • When two solutions are mixed and a solid is formed, the solid is called a precipitate. Precipitation Reactions Molarity • Solution = solute dissolved in solvent. • Solute: present in smallest amount. • Water as solvent = aqueous solutions. • Change concentration by using different amounts of solute and solvent. Molarity: Moles of solute per liter of solution. • If we know: molarity and liters of solution, we can calculate moles (and mass) of solute. Concentrations of Solutions Molarity Concentrations of Solutions litersin solution of volume solute of moles Molarity  Dilution • We recognize that the number of moles are the same in dilute and concentrated solutions. • So: MdiluteVdilute = moles = MconcentratedVconcentrated Concentrations of Solutions