Formula mass, empirical and molecular formula practice problems, Exercises of Chemistry

Download Formula mass, empirical and molecular formula practice problems and more Exercises Chemistry in PDF only on Docsity! Formula mass, empirical and molecular formula practice problems MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A 2.000 g sample of water contains 11.19% H by mass and 88.81% O by mass. What % of H by mass will be found in a 6.375 g sample of water? 1) A) 5.60% B) 88.81% C) 33.33% D) 33.57% E) 11.19% 2) A 2.000 g sample of water contains 11.19% H by mass and 88.81% O by mass. What % of H by mass will be found in a 64.57 g sample of water? 2) A) 5.60% B) 88.81% C) 33.33% D) 33.57% E) 11.19% 3) Determine the percent H by mass in NH4Cl. 3) A) 67% B) 7.537% C) 3.676% D) 14% E) 1.9% 4) Fumaric acid, C4H4O4, is a molecule found in most organisms. The percent composition of C, H and O in fumaric acid by mass is: 4) A) C 0.25% H 0.25% O 0.50% B) C 39.80% H 6.68% O 53.52% C) C 40.00% H 6.67% O 53.33% D) C 41.39% H 3.473% O 55.14% E) C 33.33% H 33.33% O 33.33% 5) What is the empirical formula for fumaric acid, C4H4O4? 5) A) CHO B) C2H2O2 C) CH2O2 D) CH4O4 E) not enough information 6) A compound was found to be comprised of 36.763% iron, 21.108% sulfur and 42.128% oxygen by mass. What is its empirical formula? 6) A) FeSO B) FeSO3 C) FeSO4 D) Fe2S2O8 E) not enough information 1 7) A compound was found to be comprised of 36.763% iron, 21.108% sulfur and 42.128% oxygen by mass. What is its empirical formula? 7) A) FeSO4 B) Fe2S2O8 C) FeSO3 D) FeSO E) not enough information 8) A compound was found to be comprised of 21.955% sulfur and 78.045% fluorine by mass. What is its molecular formula? 8) A) SF B) S2F5 C) SF5 D) SF6 E) not enough information 9) A compound was found to be comprised of 21.955% sulfur and 78.045% fluorine by mass. Using a mass spectrometer this compound was found to have a mass of 146.056 g/mol. What is its molecular formula? 9) A) SF B) SF6 C) SF5 D) S2F5 E) not enough information 10) A sample contains 43.7% phosphorus and 56.3% oxygen. What is the empirical formula of the compound? 10) A) P4O10 B) P5O8 C) PO3 D) P2O5 E) P4O5 11) A sample contains 43.7% phosphorus and 56.3% oxygen. What is the molecular formula of the compound? 11) A) P2O5 B) P4O5 C) P4O10 D) PO3 E) not enough information 12) A sample contains 43.7% phosphorus and 56.3% oxygen by mass. The molar mass is 283.89 amu. What is the molecular formula of the compound? 12) A) P4O5 B) P5O8 C) P2O5 D) PO3 E) P4O10 2