Molecular weights and percent of element by mass

Question

Assignment:

Q1. Calculate the molecular weight of the following compounds:

Al₂(SO₄)₃    ____________________    SbBr₅    ____________________

Fe(NO₃)₃    ____________________    C₉H₁₁NO₂    ____________________

Q2. Calculate the number of moles in 25 grams of each of the following compounds:

C₉H₁₁NO₂    ____________________

Al₂(SO₄)₃    ____________________

Q3. Calculate the number of grams of each in 1.25 mol of the following compounds:

Fe(NO₃)₃    ____________________

SbBr₅    ____________________

Q4. Calculate the percent of each element present in the following compounds:

C₉H₁₁NO₂    C = __________    H = __________    N = __________    O = __________

Fe(NO₃)₃    Fe = __________    N = __________    O = __________

Q5. Determine the empirical formula for the following compounds whose % compositions are given below:

49.41% C, 4.56% H, 32.87% Br, 13.16% O    ____________________

36.76% Fe, 21.11% S, 42.13% O    ____________________