H09 Gas Laws 2 - saldana(avs387 – H09 Gas Laws 2 –...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: saldana (avs387) – H09: Gas Laws 2 – Mccord – (52385) 1 This print-out should have 22 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. I’ve included some more gas stoichiome- try problems on this assignment. Practicing all aspects of stoichiometry is always a good thing in a chemistry class. Please get all sto- ichiometry related topics down pat. Chem- istry has stoichiometry at the heart of it. Learn it - live it. 001 10.0 points What is the mass of oxygen gas in a 10.3 L container at 13.0 ◦ C and 7.84 atm? Correct answer: 110 . 051 g. Explanation: T = 13 . ◦ C + 273 = 286 K P = 7 . 84 atm V = 10 . 3 L m = ? n = P V RT = (7 . 84 atm)(10 . 3 L) ( . 0821 L · atm mol · K ) (286 K) = 3 . 43909 mol O 2 m = (3 . 43909 mol) parenleftbigg 32 g mol parenrightbigg = 110 . 051 g O 2 002 10.0 points Toluene (C 6 H 5 CH 3 ) is a liquid compound similar to benzene (C 6 H 6 ). Calculate the mole fraction of toluene in the solution that contains 75.9 g toluene and 62.0 g benzene. Correct answer: 0 . 509. Explanation: m toluene = 75.9 g m benzene = 62.0 g n toulene = (75 . 9 g toluene) parenleftBig 1 mol 92 . 14 g parenrightBig = 0 . 824 mol n benzene = (62 . 0 g benzene) parenleftBig 1 mol 78 . 11 g parenrightBig = 0 . 794 mol The total number of moles of all species present is . 824 mol + 0 . 794 mol = 1 . 62 mol The mole fraction of toluene is then X toluene = n toluene n total = . 824 mol 1 . 62 mol = 0 . 509 003 (part 1 of 4) 10.0 points Iron pyrite (FeS 2 ) is the form in which much of the sulfur exists in coal. In the combustion of coal, oxygen reacts with iron pyrite to produce iron(III) oxide and sulfur dioxide, which is a major source of air pollution and a substantial contributor to acid rain. What mass of Fe 2 O 3 is produced from the reaction is 84 L of oxygen at 3 . 99 atm and 167 ◦ C with an excess of iron pyrite? Correct answer: 269 . 512 g. Explanation: P = 3 . 99 atm T = 167 ◦ C + 273 = 440 K R = 0 . 08206 L · atm K · mol V = 84 L MW Fe 2 O 3 = 2(55 . 845 g / mol) + 3(15 . 9994 g / mol) = 159 . 688 g / mol The balanced equation is 4 FeS 2 (s) + 11 O 2 (g)-→ 2 Fe 2 O 3 (s) + 8 SO 2 (g) Applying the ideal gas law to the O 2 , P V = nRT n = P V RT = (3 . 99 atm) (84 L) ( . 08206 L · atm K · mol ) (440 K) = 9 . 28256 mol . From stoichiometry and the molar mass of Fe 2 O 3 , m Fe 2 O 3 = (159 . 688 g / mol Fe 2 O 3 ) × 2 mol Fe 2 O 3 11 mol O 2 (9 . 28256 mol O 2 ) = 269 . 512 g Fe 2 O 3 . saldana (avs387) – H09: Gas Laws 2 – Mccord – (52385) 2 004 (part 2 of 4) 10.0 points If the sulfur dioxide that is generated above is dissolved to form 5 . 1 L of aqueous solu- tion, what is the molar concentration of the resulting sulfurous acid (H 2 SO 3 ) solution?...
View Full Document

{[ snackBarMessage ]}

Page1 / 7

H09 Gas Laws 2 - saldana(avs387 – H09 Gas Laws 2 –...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online