Worksheets7.4 Percentage composition, empirical and molecular formulas
Total questions: 10
Worksheet time: 13mins
Name
Class
Date
1.
What is the percent by mass of magnesium 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)
49%
d)
65%
3.
Find the percent composition of Cu2S?
a)
%Cu= 67.987 %S= 32.013
b)
%Cu= 79.854 %S= 20.145
c)
%Cu= 35.946 %S= 64.054
4.
Which of the following is considered an empirical formula?
a)
CH3COOH
b)
C6H12O6
c)
H2O
5.
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
6.
What is the empirical formula if you have 81.82% carbon and 18.18% hydrogen?
a)
C3H8
b)
CH4
c)
C2H2
d)
C4H10
7.
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
8.
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
9.
A chemical formula that shows the actual # of atoms present in a compound is called_________
a)
ionic formula
b)
covalent formula
c)
empirical formula
d)
molecular formula
10.
A compounds is made up of 30% nitrogen and 70% sulfur. The molar mass of the compound is 92 g/mol. What is the molecular formula for the compound?
a)
NS
b)
N2S2
c)
NS2
d)
N2S
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