Chemistry 07-Calculation of Molecular Formulas

October 19th

 

Problems

1) You have isolated a compound and sent it for for analysis to help determine it’s identity. The lab sends back the results indicating that the compound is 50.00 % carbon, 8.33 % hydrogen, 19.44 % nitrogen, and 22.22 % oxygen. The molecular mass of the compound is found to be 144.0 g/mol.
What is the molecular formula of the compound you isolated?

Check you answer. What are some possible suspects?

 

 

2) You have isolated a compound and sent it for for analysis to help determine it’s identity. The lab sends back the results indicating that the compound is 72.48 % carbon, 7.38 % hydrogen, 9.40 % nitrogen, and 10.73 % oxygen. The molecular mass of the compound is found to be 298.4 g/mol.
What is the molecular formula of the compound you isolated?

Check you answer. What are some possible suspects?

 

 

3) A 1.2569-g sample of a new compound has been isolated and found to contain 0.7238 g carbon, 0.07088 g hydrogen, 0.1407 g itrogen, and 0.3214 g oxygen. The molecular mass of the compound is found to be 250.3 g/mol.
What is the molecular formula of the compound you isolated?

Check you answer. What are some possible suspects?

 

 

4) What is the empirical formula of the compound that is 42.10 % carbon, 5.26 % hydrogen, 24.56 % nitrogen, and 28.07 % oxygen? If molecular mass of the compound is found to be 171.2 g/mol what is it's molecular formula?

Check you answer. What are some possible suspects?

 

5) What is the molecular mass of ibuprofen(C13H18O2)? Determine the % composition by mass for ibuprofen.

Check you answer. See structure of ibuprofen?

 

 

6) What is the molecular mass of coumarin (C9H6O2)? Determine the % composition by mass for coumarin.

Check you answer. See structure of coumarin?

 

 

 

 

 

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Last Updated:October 20, 2005