Question

The empirical formula for hemoglobin is C₇₃₈H₁₁₁₆N₈₁₂O₂₀₃S₂Fe.

The molecular formula for hemoglobin is C₂₉₅₂H₄₄₆₄N₃₂₄₈O₈₁₂S₈Fe₄

Complete combustion of hemoglobin would convert all of the iron present to Fe₂O₃.

1. Show the calculation that demonstrates that the complete combustion of a 4.824x10⁴ g sample of hemoglobin would produce 159 g of Fe₂O₃. (include units on each value in your calculation)

2. Explain how the collection of 159 g of Fe₂O₃ from the combustion of 4.824x10⁴ g of hemoglobin can be used to determine the molar mass of hemoglobin.

What is the empirical formula when: 4.44% H, 60.00% C, and 35.53% O?

A compound with the empirical formula CH₂O has a molecular weight of 90 amu. What is its molecular formula?

1. When an element, E, is burned in air, the compound E₄O₁₀ is formed. Assume that one experiment showed that 0.744 g of E produces 704 g of E₄O₁₀. Use this information to determine the ratio of atomic masses of E and E₄O₁₀, and then use the atomic mass of oxygen to determine the atomic mass of E and identify the element for which E stands. (Remember: atomic mass and molar mass are numerically equivalent.) (Hint: There isn’t enough space below to perform all of the required calculations. You should brainstorm and consider how mass, molar mass, and the ratio of elements that can be determined from the chemical formula are related to each other. Try to “see” the connections between these concepts.)