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Zumdahl and DeCoste - Chemical Principles 8/e (Homework)

James Finch

Chemistry - College, section 1, Fall 2019

Instructor: Dr. Friendly

Current Score : 1 / 30

Due : Thursday, April 2, 2020 05:00 EDT

Last Saved : n/a Saving...  ()

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Question
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1 2 3 4 5 6
–/1 –/4 –/11 –/8 –/2 –/4
Total
1/30 (3.3%)

  • Instructions

    Chemical Principles 8th edition, by Steven S. Zumdahl and Donald J. DeCoste and published by Cengage Learning, includes more than 1850 end-of-chapter problems. Questions provide links to relevant textbook pages.

    Questions 1 and 5 utilize chemPad to grade a chemical formula.

    Questions 2-4 and 6 display significant figures grading for numerical answer blanks. This demo assignment allows many submissions and allows you to try another version of the same question for practice wherever the problem has randomized values.

Assignment Submission

For this assignment, you submit answers by question parts. The number of submissions remaining for each question part only changes if you submit or change the answer.

Assignment Scoring

Your last submission is used for your score.

1. –/1 points ZumChemP8 5.AE.119. My Notes
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1
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–/1
 
A 2.769-g sample of titanium metal is reacted with excess HCl gas to produce 1.89 L of H2(g) at 380. K and 0.955 atm and a titanium chloride compound (TiClx). What is the formula of the titanium chloride compound produced in the reaction?

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TiCl2
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2. –/4 points ZumChemP8 5.AE.120. My Notes
Question Part
Points
Submissions Used
1 2 3 4
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0/100 0/100 0/100 0/100
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–/4
 
The total mass that can be lifted by a balloon is given by the difference between the mass of air displaced by the balloon and the mass of the gas inside the balloon. Consider a hot-air balloon that approximates a sphere 4.73 m in diameter and contains air heated to 63°C. The surrounding air temperature is 22°C. The pressure in the balloon is equal to the atmospheric pressure, which is 746 torr.
(a) What total mass can the balloon lift? Assume the average molar mass of air is 29.0 g/mol. (Hint: Heated air is less dense than cool air.)
WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

7900

 g

(b) If the balloon is filled with enough helium at 22°C and 746 torr to achieve the same volume as in part (a), what total mass can the balloon lift?
WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

56100

 g

(c) What mass could the hot-air balloon (from part (a)) lift if it were on the ground in Denver, Colorado, where a typical atmospheric pressure is 622 torr?
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6600

 g

(d) What mass could the hot-air balloon (from part (a)) lift if it were a cold day with a temperature of
−5°C?

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14500

 g
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3. –/11 points ZumChemP8 5.CP.161. My Notes
Question Part
Points
Submissions Used
1 2 3 4 5 6 7 8 9 10 11
–/1 –/1 –/1 –/1 –/1 –/1 –/1 –/1 –/1 –/1 –/1
0/100 0/100 0/100 0/100 0/100 0/100 0/100 0/100 0/100 0/100 0/100
Total
–/11
 
Methane (CH4) gas flows into a combustion chamber at a rate of 178 L/min at 1.09 atm and ambient temperature. Air is added to the chamber at 1.00 atm and the same temperature, and the gases are ignited.
(a) To ensure complete combustion of CH4 to CO2(g) and H2O(g), three times as much oxygen as is necessary is reacted. Assuming air is 21 mole percent O2 and 79 mole percent N2, calculate the flow rate of air necessary to deliver the required amount of oxygen.
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5500

 L air/min

(b) Under the conditions in part (a), combustion of methane was not complete as a mixture of CO2(g) and CO(g) was produced. It was determined that 92.3% of the carbon in the exhaust gas was present in the CO2. The remainder was present as carbon in the CO. Calculate the composition of the exhaust gas in terms of mole fractions of CO, CO2, O2, N2, and H2O. Assume CH4 is completely reacted and N2 is unreacted. (Enter your answers to three significant figures.)
CO     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.00260
CO2     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.0312
O2     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.136
H2O     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.0675
N2     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.762

(c) Assuming a total pressure of the exhaust gas of 1.00 atm, calculate the partial pressures of the gases in part (b). (Enter your answers to three significant figures.)
CO     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.00260

 atm
CO2     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.0312

 atm
O2     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.136

 atm
H2O     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.0675

 atm
N2     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.762

 atm
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4. –/8 points ZumChemP8 5.E.022. My Notes
Question Part
Points
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1 2 3 4 5 6 7 8
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–/8
 
A diagram for an open-tube manometer is shown below.
If the flask is open to the atmosphere, the mercury levels are equal. For each of the following situations in which a gas is contained in the flask, calculate the pressure in the flask in torr, atmospheres, and pascals. In this case ha = 142 mm and hb = 240. mm.
(a)
WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

618

 torr WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

0.813

 atm WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

82400

 Pa
(b)
WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

1.00e+03

 torr WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

1.32

 atm WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

1.33e+05

 Pa
(c)
Calculate the pressures in the flask in parts (a) and (b) (in torr) if the atmospheric pressure is 660. torr.
part (a) WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

518

 torr part (b) WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

900.

 torr
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5. –/2 points ZumChemP8 5.E.072. My Notes
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0/100 0/100
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An organic compound contains C, H, N, and O. Combustion of 0.1057 g of the compound in excess oxygen yielded 0.2303 g of CO2 and 0.0514 g of H2O. A sample of 0.4848 g of of the compound was analyzed for nitrogen by the Dumas method. At STP, 24.4 mL of dry N2 was obtained. In a third experiment the density of the compound as a gas was found to be 4.48 g/L at 112°C and 242 torr. What are the empirical formula and the molecular formula of the compound?
empirical formula:

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C11H12NO4

molecular formula:

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C22H24N2O8
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6. –/4 points ZumChemP8 5.E.081. My Notes
Question Part
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1 2 3 4
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0/100 0/100 0/100 0/100
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–/4
 
Calculate the average kinetic energies of NO2 molecules at 291 K and 550. K.
291 K     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

6.03e-21

 J/molecule
550. K     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

1.14e-20

 J/molecule

Calculate the average kinetic energies of HF molecules at 291 K and 550. K.
291 K     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

6.03e-21

 J/molecule
550. K     WebAssign will check your answer for the correct number of significant figures.(No Response) seenKey

1.14e-20

 J/molecule

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