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WorksheetsEmpirical formula & Molecular formulae
Total questions: 9
Worksheet time: 19mins
Name
Class
Date
1.
What is the percent by mass of oxygen in MgO?
a)
20%
b)
40%
c)
50%
d)
60%
2.
What is the percent by mass of fluorine in CaF2 (gram-formula mass = 78 g/mol)?
a)
24%
b)
49%
c)
51%
d)
65%
3.
What is the percent composition by mass of oxygen in the compound MgSO4 (gram formula mass = 120 g/mol)?
a)
20%
b)
27%
c)
46%
d)
53%
4.
Which pair has the same empirical formula?
a)
NaCrO4 and Na2Cr2O7
b)
C2H4O2 and C6H12O6
c)
C3H6O3 and C2H6O2
d)
CH4 and C2H6
5.
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
6.
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
7.
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
8.
Which of these is NOT an empirical formula?
a)
CH2
b)
C2H5
c)
C6H4
d)
C3H7
e)
C5H17
9.
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
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