WA 3 Dearing

.docx

School

Thomas Edison State College *

*We aren’t endorsed by this school

Course

121

Subject

Chemistry

Date

Apr 3, 2024

Type

docx

Pages

2

Uploaded by MagistratePantherMaster1075

Report
Name: Eric Dearing College ID: 0550796 Thomas Edison State College General Chemistry I with Labs (CHE-121) Section no.: Semester and year: May 2014 Written Assignment 3: Mass Relationships for Compounds Answer all assigned questions and problems, and show all work. 1. How many atoms are there in 5.10 moles of sulfur (S)? (6 points) 5.10 X (6.02 X 10 23 ) = 3.07 E24 atoms of sulfur (Reference: Chang 3.13) 2. How many moles of calcium (Ca) atoms are there in 77.4 g of Ca? (6 points) 77.4 g / 40.078 = 1.86 moles of calcium (Reference: Chang 3.15) 3. What is the mass in grams of 1.00 × 10 12 lead (Pb) atoms? (8 points) (1.00 × 10 12 ) X 207.2 = 2.07 x 10 14 / 6.022 x 10 23 = 3.44 x 10 -10 (Reference: Chang 3.19) 4. Describe how you would determine the isotopic abundance of an element from its mass spectrum. (6 points) The mass spectrometer takes a gaseous sample and bombards it with highly charged electrons that dislodge electrons from the sample therefore producing positive ions. The positive ions are then accelerated by 2 oppositely charged plates. As the ions pass through the plates they are deflected into a circular pattern based on the charge to mass ration (e/m). The ions arrive at a detector, which measures the current. The amount of current is directly proportional to the number of ions and is used to determine the abundance of isotopes. (Reference: Chang 3.32) 5. Cinnamic alcohol is used mainly in perfumery, particularly in soaps and cosmetics. Its molecular formula is C 9 H 10 O. Calculate the percent composition by mass of C, H, and O in cinnamic alcohol. (8 points) C = 80.5%, H = 7.5%, O = 11.9% a. How many molecules of cinnamic alcohol are contained in a sample of mass 0.469 g? (8 points) .469 x (6.022 x10 23 ) = 2.82 x 10 23 b. How many carbon atoms are in 0.469 g of cinnamic alcohol? (8 points) (2.82 x 10 23 ) x 0.81 = 2.3 x 10 23 (Reference: Chang 3.41) 1
6. Allicin is the compound responsible for the characteristic smell of garlic. An analysis of the compound gives the following percent composition by mass: C: 44.4 percent; H: 6.21 percent; S: 39.5 percent; O: 9.86 percent. Calculate its empirical formula. C 3.7 H 6.2 S 1.2 0 .6 What is its molecular formula given that its molar mass is about 486g? (20 points) C 6 H 10 S 2 O (Reference: Chang 3.43) 7. Tin(II) fluoride is often added to toothpaste as an ingredient to prevent tooth decay. What mass of fluoride in grams is in 258 g of toothpaste that has 15% tin(II) fluoride? (10 points) 258g x 0.15% = 38.7g of SnF 2 Sn + F 2 = 118.7 + 19 + 19 = 156.69 g/mol 38 / 157 = 24% 24% of 38.7g = 9.3g of Fluoride 8. What are the empirical formulas of the compounds with the following compositions? (a) 2.1 percent H, 65.3 percent O, 32.6 percent S = H 2 SO 4 2.1g H, 2.1/1.00794 = 2.08 65.3g O, 65.3/15.9994 = 4.08 32.6g S, 32.6/32.066 = 1.01 Divide subscripts by smallest subscript 2.08/1.01 = 2.06, 4.08/1.01 = 4.03 = H 2.06 O 4.03 S 1.01 (b) 20.2 percent Al, 79.8 percent Cl (20 points) = AlCl 3 20.2g Al, 20.2/26.981538 = 0.748 79.8g Cl, 79.8/35.4527 = 2.25 Divide subscripts by smallest subscript 2.25/0.748 = 3.00 = Al 0.7 Cl 2.3 (Reference: Chang 3.49) 2
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help
Recommended textbooks for you
Text book image
Chemistry
Chemistry
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Cengage Learning
Text book image
Chemistry: An Atoms First Approach
Chemistry
ISBN:9781305079243
Author:Steven S. Zumdahl, Susan A. Zumdahl
Publisher:Cengage Learning
Text book image
Chemistry
Chemistry
ISBN:9781133611097
Author:Steven S. Zumdahl
Publisher:Cengage Learning
Text book image
Chemistry & Chemical Reactivity
Chemistry
ISBN:9781337399074
Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
Publisher:Cengage Learning
Text book image
Chemistry & Chemical Reactivity
Chemistry
ISBN:9781133949640
Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
Publisher:Cengage Learning
Text book image
General Chemistry - Standalone book (MindTap Cour...
Chemistry
ISBN:9781305580343
Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; Darrell
Publisher:Cengage Learning
SEE MORE TEXTBOOKS
Recommended textbooks for you
  • Text book image
    Chemistry
    Chemistry
    ISBN:9781305957404
    Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
    Publisher:Cengage Learning
    Text book image
    Chemistry: An Atoms First Approach
    Chemistry
    ISBN:9781305079243
    Author:Steven S. Zumdahl, Susan A. Zumdahl
    Publisher:Cengage Learning
    Text book image
    Chemistry
    Chemistry
    ISBN:9781133611097
    Author:Steven S. Zumdahl
    Publisher:Cengage Learning
  • Text book image
    Chemistry & Chemical Reactivity
    Chemistry
    ISBN:9781337399074
    Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
    Publisher:Cengage Learning
    Text book image
    Chemistry & Chemical Reactivity
    Chemistry
    ISBN:9781133949640
    Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
    Publisher:Cengage Learning
    Text book image
    General Chemistry - Standalone book (MindTap Cour...
    Chemistry
    ISBN:9781305580343
    Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; Darrell
    Publisher:Cengage Learning
Text book image
Chemistry
Chemistry
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Cengage Learning
Text book image
Chemistry: An Atoms First Approach
Chemistry
ISBN:9781305079243
Author:Steven S. Zumdahl, Susan A. Zumdahl
Publisher:Cengage Learning
Text book image
Chemistry
Chemistry
ISBN:9781133611097
Author:Steven S. Zumdahl
Publisher:Cengage Learning
Text book image
Chemistry & Chemical Reactivity
Chemistry
ISBN:9781337399074
Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
Publisher:Cengage Learning
Text book image
Chemistry & Chemical Reactivity
Chemistry
ISBN:9781133949640
Author:John C. Kotz, Paul M. Treichel, John Townsend, David Treichel
Publisher:Cengage Learning
Text book image
General Chemistry - Standalone book (MindTap Cour...
Chemistry
ISBN:9781305580343
Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; Darrell
Publisher:Cengage Learning
SEE MORE TEXTBOOKS