## CHE 011

CHE 011 Homework 6 Name:

You can either type your calculations and answers directly into this document or you can write them out on the piece of paper.

For numerical problems, calculation set up must be shown

To calculate molar masses, use the values of atomic masses with 2 DP from the Periodic Table provided at the last page.

1. You have a 329.4-gram sample of gold(III) sulfide, Au2S3. After various chemical and physical processes, you are able to separately measure 264.8 grams of gold and 64.6 grams of sulfur.

What are the experimental mass percents of the two elements in this compound?

Answer: %Au = % S =

2. Use molar masses to calculate the theoretical percent of gold and sulfur in gold(III) sulfide, Au2S3.

Answer: %Au = % S =

3. Suppose a certain compound is known to be 47% copper, by mass. How many grams of copper will there be in a 12.5 gram sample of this compound?

4. Fill in what items are being counted for each substance. The choices are: molecules, atoms, formula units. Include the substance in your answer.

1. 1 mole of silver, Ag = 6.022⨯1023 _____ __________
2. 1 mole of methane, CH4 = 6.022⨯1023 ______ __ _____
3. 1 mole of chlorine gas, Cl2 = 6.022⨯1023 ______ __ _________
4. 1 mole of gold(III) sulfide, Au2S3 = 6.022⨯1023 _______ __________

5. Calculate the molar mass for each of the following substances. Use the Periodic Table provided at the last page. Use these calculated values for questions #6-13 as needed.

a. ammonia, NH3 __

b. glucose, C6H12O6 ____

c. carbon dioxide, CO2 ____

For questions #6-13, fill in the requested information to figure out how to set up the calculation. Then do the calculation a separate sheet of paper and round off the answer to the correct significant figures.

6. How many ammonia molecules are there in 16.78 moles of NH3 ?

Starting Unit (include substance):

Ending Unit (include substance):

Tool(s) needed:

Calculation set up:

7. How many moles of ammonia molecules are there in 789 grams of NH3 ?

Starting Unit (include substance):

Ending Unit (include substance):

Tool(s) needed:

Calculation set up:

8. How many moles of tin, Sn are needed to give 1.39x1022 tin atoms ?

Starting Unit (include substance):

Ending Unit (include substance):

Tool(s) needed:

Calculation set up:

9. How many grams of glucose, C6H12O6 are there in 5.7×1021 glucose molecules ?

Starting Unit (include substance):

Ending Unit (include substance):

Tool(s) needed:

Calculation set up:

10. How many moles of chromium are there in 24.61 moles of aluminum dichromate, Al2(Cr2O7)3 ?

Starting Unit (include substance):

Ending Unit (include substance):

Tool(s) needed:

Calculation set up:

11. How many grams of carbon dioxide are there in 0.0364 moles of CO2 ?

Starting Unit (include substance):

Ending Unit (include substance):

Tool(s) needed:

Calculation set up:

12. How many glucose molecules are there in 7.649 grams of glucose, C6H12O6 ?

Starting Unit (include substance):

Ending Unit (include substance):

Tool(s) needed:

Calculation set up:

13. How many oxygen atoms are there in 64 moles of carbon dioxide, CO2 ?

Starting Unit (include substance):

Ending Unit (include substance):

Tool(s) needed:

Calculation set up:

## Molecule Paper

Requirements for Molecule Paper

Due date is Monday, August 15 th, at 11:59 PM.

1. The text of the paper must be at least 4 pages in length.

One page must contain a hand-drawn molecular structure in ink showing hybridizations and bond angles, with a list of chemical and physical properties. The last page must be a bibliography, clearly showing the references used for the paper. Make sure journal articles are cited properly, including journal title, year, volume, number, author, article title and pages. Total length of the paper should be 4-5 pages, so that leaves 2-3 pages of actual writing.

1. Format the paper using 1-inch margins, double spacing and Times Roman 12-point font.
2. A minimum of Four (4) references is required. One reference must be The Merck Index, the best place to find the chemical/physical properties and a structure.

https://library.shoreline.edu/MerckIndex

4. One must be a peer-reviewed scientific journal about your molecule from Shoreline

database.

Two magazine articles websites (for example: the Encyclopedia of Science and

Technology) are a good source for current applications and information. No more than

two websites may be used, and they must be credible websites, i.e., .edu, .gov. Wikipedia

does not count as an acceptable reference, but it is

a good starting point.

5. Include the following information on your molecule, as appropriate. Not all information will be available for all molecules, but something in each section must be present.

a. Background: discoverer, date discovered, origin of name, source, first known use, history, developing company, etc.

b. Major uses or industrial importance – keep to two or three uses, how it works or achieves desired effect if applicable.

c. Anything else of interest – here is where any unusual/unexpected uses, side effects, applications or issues discovered during your research should be presented. This is the fun part!

d. Include on a separate page: hand-drawn structure showing hybridization and bond angles, physical and chemical properties including toxicity (if any).

6. Treat this as an English composition. Use complete sentences and coherent paragraphs. Although I am not an English teacher, I will consider spelling and grammar in the grade. It is a very good idea to make use of the Reading/Writing Center and the grammar/spell check function in Word.