1. Stoichiometry and Gases By: Carson Ram & Thomas Schweinfurth

2. The Periodic Table Atomic Number: Representative of the protons Atomic Symbol: Letter representation of the element Atomic Weight: Representative the neutrons & protons

3. The Periodic Table Period: Across a row Family: Down a column Metals Metalloids Nonmetals http://wps.prenhall.com/wps/media/objects/5524/5656731/ebook/blb11_flash_main.html?chapter=null&page=null&anchory=null&pstart=null &pend=nuall 1A: Alkaline 2A: Alkaline Earth Metals ChalcogensChalcogens HalogensHalogens 8A: Noble Gases

4. Atoms, Molecules, and Ions Molecular Formulas: Indicate the actual numbers and types of atoms in a molecule Empirical Formulas: Give only the relative number of atoms of each type in a molecule Example… Molecular Formula C 2 H 4 Empirical Formula CH 2

5. Chemical Nomenclature Tips & Tricks for naming cations: – Cations formed from metal atoms have the same name as the metal: Ex. Ca +2  calcium ion – If a metal can form different ions, the positive charge is indicated by a Roman numeral in parenthesis behind the name of the metal: Ex. Fe 2+  iron (II) ionFe 3+  iron (III) ion – Cations formed from nonmetal atoms have names that end in –ium: NH 4 +  ammon-ium ionH 3 O +  hydron-ium ion

6. Chemical Nomenclature Tips & Tricks for naming anions: (Part One) – The names of monatomic anions are formed by replacing the ending of the name of the element with –ide: Ex. Br -  Brom-ide IonCl -  Chlor-ide Ion – Polyatomic anions containing oxygen have names ending in –ate or –ite. Ex. NO 3 -  Nitr-ate Ion NO 2 -  Nitr-ite Ion – The Prefix per- indicates one more atom than the ion ending in –ate. – The Prefix hypo- indicates one fewer atom than the ion ending in –ites.

7. Chemical Nomenclature Tips & Tricks for naming anions: (Part Two) – Anions derived by adding H + to any oxyanion are named by adding as a prefix the word hydrogen or dihydrogen, as appropriate. Ex. PO 4 3-  phosphate HPO 4 2-  hydrogen phosphate H 2 PO 4 -  dihydrogen phosphate – Names of ionic compounds consist of the cation name followed by the anion name Ex. NaCl  Sodium Chloride

8. Structuring Q : The Charge Z : Atomic Number A : Mass Number

9. Percentage Compostitions Formula Weight: Sum of the atomic weights of each atom in its chemical formula. Example: Calculate the percentage of carbon in C 12 H 22 O 11. Addition of Atomic Weights: 12 C atoms = 12 (12.0 amu) = 144.0 amu 22 H atoms = 22 (1.0 amu) = 22.0 amu 11 O atoms = 11 (16.0 amu) = 176.0 amu 342.0 amu Atomic Weight of Carbon: 12.0 amu

10. Avogadro’s Number Named after Amedeo Avogadro (1776-1856) N A = 6.02 x 10 23 atoms / 1 mol 1 mol ‘Element’ = 6.02 x 10 23 atoms 1 mol ‘Compound’ = 6.02 x 10 23 molecules 1 mol ‘Ions’ = 6.02 x 10 23 ions

11. Limiting Reactants Limiting Reagent: Determines, or limits, the amount of product formed. Left over reactants are often called excess reactants. Theoretical Yield: Quantity of product calculated to form Actual Yield: Quantity of product actually obtained

12. Gases Standard temperature and pressure (STP) is 273.15 K and 1 atm. – 1 atm = 760 mm Hg = 760 torr = 101.325 kPa Boyle’s Law: States that the volume of a fixed quantity of gas maintained at constant temperature is inversely proportional to the pressure. – PV = constant Charles’s Law: States that the volume of a fixed quantity of gas maintained at a constant pressure is directly proportional to the absolute temperature. – V / T = constant

13. Gases Avogadro’s Hypothesis: Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. Avogadro’s Law: states that the volume of a gas maintained at constant temperature and pressure is directly proportional to the number of moles in the gas. – V / n = constant

14. Ideal Gas Law The ideal-gas equation is… PV = nRT. R is the gas constant. – R=8.314 J/molKR=0.08206 Latm/molK Remember! Temperature is in Kelvins, not degrees Celsius.

15. More About Gases If n and T are constant, the values of P and V can change, but the product of PV must remain constant, so: – P 1 V 1 =P 2 V 2 When just n is constant, P,V, and T can all change but the product of (PV)/T must remain constant so: – (P 1 V 1 )/T 1 =(P 2 V 2 )/T 2  Often called the combined gas law

16. Partial Pressure The total pressure of a mixture of gases equals the sum of the pressures that each would exert if it were present alone: – P t = P 1 +P 2 +P 3 Each gas in a mixture behaves independently so we can relate the amount of a given gas in a mixture to its partial pressure: – P 1 / P t = (n 1 RT/V) / (n t RT/V) = n 1 /n t  mole fraction – P 1 =(n 1 /n t )P t

17. Graham’s Law and rms Speed Particles with lighter masses have a higher rms speed. – u=M is molar mass Graham’s law states that if we have two gases at the same temperature and pressure in containers with identical pinholes, and r is the rate of diffusion, then: – r 1 /r 2 =

18. Van der Waals Van der Waals recognized that the ideal gas equation could be corrected to account for the effects of attractive forces between gas molecules and for molecular volumes. Constant a is a measure of how strongly the gas molecules attract each other and constant b is a measure of the small but finite volume occupied by the gas molecules themselves. (P+(n 2 a)/V 2 )(V-nb)=nRT

19. Thanks to… Chemistry: The Central Science by T. Brown, H. LeMay, B. Bursten, and C. Murphy