5. By mass, this compound is made up of 30.4% N and 69.6% O. What is the correct chemical formula of this compound?
a. NO3
b. NO
c. NO2
d. N2O3
6. The atomic mass of C is 12 amu while H is 1 amu. The molar mass of CH4 is 16 g/mol. What is the percentage composition of CH4?
a. 50% C; 50% H
b. 90% C; 10% H
c. 12% C; 16% H
d. 75% C; 25% H
7. Phosphoric acid is a clear and odorless liquid found in carbonated beverages. What is the percentage composition by mass of H?
a. 31.61%
b. 3.061%
c. 6.20%
d. 65.31%
8. What is the molecular formula of a compound having an empirical formula of C2H5O and a molecular mass of 90 g/mol?
a. C5H14O
b. C4H26O
c. C4H10O2
d. C3H6O3
9. Which of the following is the empirical formula of alkanes with a molar mass of 58 g/mol?
a. C2H5
b. C4H10
c. CH2.5
d. C8H20
10. Which of the following sets of empirical formula, molar mass, and molecular formula is correct?
a. C6H12O6, 342 g/mol, C12H22O11