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WorksheetsEmpirical and Molecular Formulas
Total questions: 21
Worksheet time: 34mins
Name
Class
Date
1.
A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?
a)
Mg4N3
b)
MgN2
c)
Mg3N2
d)
MgN
2.
You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.
a)
SO
b)
SO2
c)
SO3
d)
SO4
3.
Given the following: 42.07% Na, 18.89% P, and 39.04% O, determine the empirical formula.
a)
NaPO2
b)
Na2PO3
c)
Na3PO4
d)
NaPO4
4.
What is the molecular formula for a compound with the empirical formula: K2SO4 and a molecular mass of 696g.
a)
K2SO4
b)
K8SO16
c)
K8S4O8
d)
K8S4O16
5.
What is the percent by mass of sodium in NaCl?
a)
39%
b)
61%
c)
35%
d)
65%
6.
A formula with the lowest whole # ratio of elements in a compound is called
a)
Molecular Formula
b)
Chemical Formula
c)
Empirical Formula
d)
Distance Formula
7.
Si2F6
Choose the correct empirical formula...
a)
SiF
b)
Si2F6
c)
SiF3
d)
Si6F2
8.
What is the empirical formula for N2S3?
a)
NS
b)
N3S2
c)
N2S3
d)
N1S1.5
9.
C2F6
Choose the correct empirical formula...
a)
CF
b)
C2F6
c)
C6F2
d)
CF3
10.
A chemical formula that shows the actual # and kinds of atoms present in one molecule of a compound is called_________
a)
ionic formula
b)
covalent formula
c)
empirical formula
d)
molecular formula
11.
What is the best definition for subscript?
a)
The big number that tells you the number of molecules.
b)
The atomic number
c)
The little number that tells the number of atoms for each element.
12.
How many "C" are in CO2
a)
2
b)
1
c)
0
d)
3
13.
How many Carbons "C" are in C18H34O3
a)
18
b)
34
c)
3
d)
37
14.
Which pair has the same empirical formula?
a)
NaCrO4 and Na2Cr2O7
b)
C2H4O2 and C6H12O6
c)
C3H6O3 and C2H6O2
d)
CH4 and C2H6
15.
What is the molecular formula if the empirical formula is CH2O and the molecular molar mass is 180.18?
a)
CH2O
b)
C2H4O2
c)
C4H8O4
d)
C6H12O6
16.
What is the percent by mass of oxygen in MgO?
a)
20%
b)
40%
c)
50%
d)
60%
17.
Which one is an empirical formula?
a)
H2O2
b)
C2H6O12
c)
CaCl2
d)
N2O8
18.
Which of these is NOT an empirical formula?
a)
CH2
b)
C2H5
c)
C6H4
d)
C3H7
e)
C5H17
19.
Which of the following could be a molecular formula with the empirical formula of CH2O?
a)
CH2O2
b)
CHO
c)
C3H5O3
d)
C2H4O2
20.
What is the empirical formula of K2SO4?
a)
K2SO4
b)
KSO2
c)
K2SO2
d)
KSO8
21.
What is the molecular formula if the empirical formula is C2H5 and the molecular molar mass is 58.14 g/mol?
a)
C2H5
b)
C4H10
c)
C1H2.5
d)
C4H8
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