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# q1w1.key - Dr Zellmer Time 23 mins Chemistry 122 Summer...

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Dr. Zellmer Chemistry 122 Wednesday 9:30 AM Time: 23 mins Summer Quarter 2008 June 25, 2008 Quiz I Name KEY Rec. Instr. 9:30 ---------------------------------------------------------------------------------------------------------------------------------------- 2 1. (6 pts) Consider a steel tank whose volume is 42.0 L and which contains O gas at a pressure of 2 17997.25 kPa at 25°C. What volume would the gas occupy at STP? (Mol. Wt.: O = 32.00) (1 atm = 101.325 kPa = 14.7 lb/in = 760 torr = 760 mm Hg) 2 STP => Standard Temp. & Pressure: T = 0°C (273.15K) & P = 1 atm Since P, V & T all change use the Combined Gas Law: 22 11 PV PV ------- = ------- T MUST be in kelvin 21 T T 1 P = 17997.25 kPa V = 42.0 L T = 25°C + 273.15 = 29 8 .15 K 101.325 kPa 2 P = 1 atm × ---------------- = 101.325 kPa V = ? T = 0°C + 273.15 = 273.15 K 1 atm 112 1 2 P V T P 17997.25 kPa 273.15 K V ----------- (-----)(-----)V = (-----------------)(-------------) 42.0 L = 68 3 4 L = 6.83 x 10 L 3 2 1 P T 101.325 kPa 29 8 2. (6 pts) A gas with a molecular weight of 48.0 amu occupies a volume of 20.0 L at a pressure of 1.5 atm and a temperature of 25.0°C. What is the mass of the gas? Want mass given M (molar mass) & P, V, T data; m mass M ---- --------- n moles need moles, n => Use Ideal Gas Law : PV = nRT (1.5 atm) (20.0 L) ------ --------------------------------------------- 1. 2 2618 mol RT (0.08206 L C atm/mol C K) (298.15 K) C M 2 2618 mol x 48.0 g/mol = 5 8 .856 g = 59 g (3 s.f.) ---------------------------------------------- Could use, RT RT m RT M = (------) D = (------) (------) = (------) m P P V PV

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8 3. (3 pts) Sulfur burns in oxygen according to the following equation.
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## This note was uploaded on 07/17/2008 for the course CHEM 122 taught by Professor Zellmer during the Summer '07 term at Ohio State.

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q1w1.key - Dr Zellmer Time 23 mins Chemistry 122 Summer...

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