Mr. Scull
2/2/2023
Chapter 9 Exam
Sections 9.1, 9.2, 9.3, & 9.4
a.) Determine the Molar Mass of the following compound.
1.) (NH4)3PO4
2.) O2Cl4
3.) CuClO3
4.) Mg(OH)2
b.) Determine the % composition of the following elements.
5.) What % of chlorine is found in O2Cl4
6.) What % of chlorine is found in CuClO3?
7.) What % of Oxygen is found in Mg(OH)2?
c.) Solve the following to find the empirical formula.
8.) What is the empirical formula for a compound that consist of 74.47% C, 8.75% H, and
17.36 % N?
9.) Find the empirical formula of a compound that contains 81.82 g carbon and 18.18 g
hydrogen.
10.) What is the empirical formula for a compound that contains 10.89% Mg, 31.77% Cl and
57.34% O?
d.) For the following molecular formulas, give the empirical formulas.
11.) C6H12O6
12.) N3Br27
e.) Make the following conversions.
14.) How many molecules are found in 2.94 moles of CO2?
15.) How many moles are found in 79.2 grams of Fe?
16.) How many moles contain 5.92 x 1024 atoms of P?
17.) How many molecules are in 74.8 grams of NaNO3 ?
18.) What is the mass (grams) of 3.71 x 1025 molecules of NaCl?
13.) O15F24
f.) Solve the following to find the empirical formula & molecular formula.
19.) Analysis of a chemical used in photographic developing fluid yielded the percent
composition of 65.45 % C, 5.45 % H, and 29.09 % O. The chemical molar mass is
110g/mole. What is the molecular formula?
20.) A compound was found to contain 49.98 g of carbon and 10.47 g of hydrogen. The molar
mass of the compound is 58.12 g/mole. Determine the molecular formula.