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WorksheetsCalculating Average Atomic Mass
Total questions: 10
Worksheet time: 18mins
Name
Class
Date
1.
4.35% of all X atoms have a mass of 39.946 amu. 83.79% have a mass of 41.941 amu, 9.50% have a mass of 42.941 amu, and 2.36% have a mass of 43.939 amu. What is the average atomic mass of atom X?
a)
41.97 amu
b)
42.19 amu
c)
10.43 amu
d)
40.04 amu
2.
Compute the average atomic mass for silicon:
a)
27.977
b)
28.09
c)
28.976
d)
The average mass cannot be determined from provided information.
3.
24.1% of all the isotopes of a an element have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu.
How many protons does this element have?
How many protons does this element have?
a)
32
b)
33
c)
34
d)
no way to know
4.
An element has three different isotopes. One has a mass of 35.00 amu; another has a mass of 36.00 amu; and another has a mass of 38.00 amu. What is the average atomic mass of this element?
a)
36.33 amu
b)
37.00 amu
c)
12.11 amu
d)
impossible to tell
5.
An element with 4.35% have a mass of 49.9461 amu, 83.79% have amass of 51.9405 amu, 9.50% have a mass of 52.9407 amu, and 2.36% have a mass of 53.9389amu.
a)
51.99 amu
b)
52.19 amu
c)
53.45 amu
d)
17.33 amu
6.
An isotope has three forms. 30% have a mass of 4 amu, 20% have a mass of 5 amu and 50% have a mass of 3 amu. Average atomic mass will be closest to
a)
2 amu
b)
3 amu
c)
4 amu
d)
5 amu
7.
Calculate the average atomic mass of silver.
a)
106.38649amu
b)
111.91896amu
c)
107.8677amu
d)
121
8.
An element has two naturally occurring isotopes. One is 10.013 amu and is 19.9% abundant. The other is 11.01 amu and is 80.1% abundant. What is the average atomic mass? What element is it?
a)
9.012, Beryllium
b)
12.011, Carbon
c)
6.941, Lithium
d)
10.812, Boron
9.
What is the name of the atom pictured here?
a)
Nitrogen
b)
Nitrogen-15
c)
Nitrogen-7
d)
Nitrogen-8
10.
Which of the following could have 82 neutrons?
a)
W-182
b)
Ta-181
c)
Cs-132
d)
Ba-138
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