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Learn about substances that exist as gases, the gas laws, the ideal gas equation, gas stoichiometry, and Dalton's Law of Partial Pressures in this comprehensive chapter.
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1 Chapter 5 (Gases) semester 1/2018 5.1 Substances that Exist as Gases 5.3 The Gas Laws 5.4 The Ideal Gas Equation 5.5 Gas Stoichiometry 5.6 Dalton’s Law of Partial Pressures
5.1 Substances that Exist as Gases Gases (Normal atmospheric condition = 25°C & 1 atm) (i) Take the volume and shape of their containers (ii) Most compressible (iii) Mix evenly and completely when confined to the same container (iv) Low Densities Atmospheric Pressure -Pressure exerted by Earth’s atmosphere (measured by “Barometer”) 1 atm = 760 torr =7 60 mmHg = 76 cm Hg 2
5.3 The Gas Laws Boyle’s Law Charle’s &Gay-Lussac Law • Mathematical Expression • (T, n constant) V T ( P, n constant) (or) P T (V,n const.) (ii) Problem Solving (iii) Graphical Presentation P(atm) P(atm) P(atm) 3 V (L) T(k)
Avogadro’s Law n=no. of moles m=mass in (g) M=molar mass d=density R=ideal gas constant for 1 mole of any gas 5.4 The Ideal Gas Equation B. Law….. C.Law….. A.Law…. Combining… 4
5.5 GAS STOICHIOMETRY Two Greek Words STOICHEION METRON i.e ELEMENT MEASURE i.e – CALCULATION ABOUT MASSES (SOMETIMES VOLUMES) OF REACTANTS & PRODUCTS. - VERY MATHEMATICAL PART OF CHEMISTRY Mass Mole of reactant Mole of product Mass of Product 5
5.6DALTON’S LAW OF PARTIAL PRESSURE THE TOTAL PRESSURE OF A MIXTURE OF GASES IS JUST THE SUM OF THE PRESSURES THAT EACH GAS WOULD EXERT IF IT WERE PRESENT ALONE. • PT = PA+PB+PC+…….. • PA = XAPT XA= • PB = XBPT………etc. • XB = • X = MOLE FRACTION NOTE : FOR COLLECTION OF GAS OVER WATER ALWAYS DEDUCT WATER VAPOR PRESSURE FROM TOTAL PRESSURE i.e 6