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WorksheetsCompound Stoich (molar mass, percent, empirical formula)
Total questions: 17
Worksheet time: 39mins
Name
Class
Date
1.
The molar mass of an element is equal to its...
a)
Atomic mass
b)
Atomic number
c)
Oxidation number
d)
Valence electrons
2.
What is the molar mass of table salt (NaCl)?
a)
116.886 g/mol
b)
35.453 g/mol
c)
22.990 g/mol
d)
58.443 g/mol
3.
What is the molar mass of CO2?
a)
12
b)
16
c)
32
d)
44
4.
Calculate the molar mass of Ba(C2H3O2)2
a)
255.3 g/mol
b)
237.3 g/mol
c)
228.3 g/mol
d)
196.3 g/mol
5.
Calculate the molar mass for Al(OH)3
a)
78.0 g/mol
b)
72 g/mol
c)
28 g/mol
d)
25 g/mol
6.
What is the Molar Mass of Potassium Sulfide?..... :-) You get to figure out the formula.
a)
110.262 g/mol
b)
71.164 g/mol
c)
174.258 g/mol
d)
158.259 g/mol
7.
What is the percent by mass of oxygen in MgO?
a)
20%
b)
40%
c)
50%
d)
60%
8.
What is the percent by mass of magnesium in MgO?
a)
20%
b)
40%
c)
50%
d)
60%
9.
What is the percent by mass of sodium in NaCl?
a)
39%
b)
61%
c)
35%
d)
65%
10.
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%
11.
In which compound is the percent composition by mass of Cl equal to 42%?
a)
HClO (gram formula mass = 52 g/mol)
b)
HClO2 (gram formula mass = 68 g/mol)
c)
HClO3 (gram formula mass = 84 g/mol)
d)
HClO4 (gram formula mass = 100 g/mol)
12.
What is the percent composition of benzene, C6H6?
a)
C = 50.%
H = 50.%
b)
C = 85.7 %
H = 14.3%
c)
C = 92.2%
H = 7.8%
d)
C = 71.9%
H = 28.1%
13.
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
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.
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
16.
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
17.
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
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