WorksheetsMoles and Percentage Composition
Total questions: 19
Worksheet time: 20mins
Name
Class
Date
1.
How to calculate molar mass of H2O?
a)
2+16=18
b)
1+16=17
c)
2+32=34
d)
1+31=32
2.
What is the molar mass of CO2?
a)
12 g/mol
b)
16 g/mol
c)
32 g/mol
d)
44 g/mol
3.
Find the percentage composition of Mg in Mg3(PO4)2.
a)
27.48% Mg
b)
43.11% Mg
c)
16.00% Mg
d)
12.63% Mg
4.
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
5.
Which of the following is NOT needed to calculate percent composition?
a)
Mass of specific element
b)
Molar Mass
c)
Avogadro's Number
d)
Division
6.
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
7.
What is the percent by mass of sodium in NaCl?
a)
39%
b)
61%
c)
35%
d)
65%
8.
What is the mass percentage of Carbon in Carbon dioxide (CO2)?
a)
27.27%
b)
42.86%
c)
72.73%
d)
72.72%
9.
What are the units in molar mass?
a)
grams
b)
moles
c)
moles/gram
d)
grams/mole
10.
The molar mass of an element is equal to its...
a)
Atomic mass
b)
Atomic number
c)
Oxidation number
d)
Valence electrons
11.
Find the molar mass of KCl
a)
36 g/mol
b)
78 g/mol
c)
74 g/mol
d)
178 g/mol
12.
What is the molar mass of fluorine gas, F2?
a)
18.998 g/mol
b)
38 g/mol
c)
9 g/mol
d)
18 g/mol
13.
Which list of number of atoms in MgF2 is right?
a)
Mg : 1-- F : 1
b)
Mg : 1 -- F : 2
c)
Mg : 2 -- F : 1
d)
Mg : 0 -- F : 1
14.
Which list of number of atoms in Mg(NO3)2 is right?
a)
Mg : 1--NO : 6
b)
Mg : 1-- N : 6--O: 6
c)
Mg : 1-- N: 1-- O: 5
d)
Mg : 1-- N: 2-- O: 6
15.
What is the percentage of OH– in Ca(OH)2?
a)
45.9%
b)
75%
c)
66.6%
d)
90.1%
16.
How many moles are there in 425.0 g of sodium chloride (NaCl)?
a)
9.835 mol
b)
8.126 mol
c)
7.272 mol
d)
6.691 mol
17.
What is the mass of 5.55 moles of carbon monoxide (CO)?
a)
155 g
b)
143 g
c)
138 g
d)
122 g
18.
The mass % of aluminum in aluminum sulfate Al2(SO4)3 is:
a)
12.93%
b)
45.70%
c)
7.89%
d)
35.94%
e)
15.77%
19.
The mass % of H in methane (CH4) is:
a)
75%
b)
92%
c)
25%
d)
4%
e)
6%
100 %
