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Copy of Percent Comp, Empirical Formula, and Molecular Formula (5/28/2026)
By Jason Poe
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Last updated about 2 hours ago
9 questions
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Question 1
1.
What is the percent composition of NH
3
?
a.) N _______ %
b.) H _______ %
Question 2
2.
What is the percent composition of Na
2
S
2
O
3
?
a.) Na _______ %
b.) S _______ %
c.) O _______ %
Question 3
3.
What is the percent composition of Ca
3
(PO
4
)
2
?
a) Ca _______ %
b.) P _______ %
c.) O _______ %
Question 4
4.
What is the empirical formula for a compound comprising 43.6% phosphorus (P) and 56.4% oxygen (O)?
a.) Molar composition (step 1 -
pay attention to Sigfigs
):
P _______ mol
O _______ mol
b.) Molar ratios (step 2 -
round to nearest whole number
):
P _______
O _______
c.) Empirical formula: _______
Question 5
5.
What is its molecular formula if the compound from question 4 has a molecular mass of 283.88 g/mol?
a.) Empirical Mass _______
b.) Formula Units _______
c.) Molecular Formula _______
Question 6
6.
What is the empirical formula for a compound comprising 40.0% carbon (C), 6.7% hydrogen (H), and 53.3% oxygen (O)?
a.) Molar composition (step 1 -
pay attention to Sigfigs
):
C _______ mol
H _______ mol
O _______ mol
b.) Molar ratios (step 2 -
round to nearest whole number
):
C _______
H _______
O _______
c.) Empirical Formula: _______
Question 7
7.
What is its molecular formula if the compound from question 6 has a molecular mass of 360.36 g/mol?
a.) Empirical mass? _______
b.) Formula Units? _______
c.) Molecular Mass? _______
Question 8
8.
A compound is comprised of 1.61% H, 22.23% N, and 76.16% O. If it has a molecular mass of 63.01 g/mol, what is the molecular formula?
a.) Empirical formula _______
b.) Empirical Mass _______
c.) Formula Units _______
d.) Molecular Formula _______
Question 9
9.
A compound has an empirical formula of C
3
O and a molecular mass of 104.06 g/mol. What is the molecular formula?
Molecular formula _______