# Average atomic mass worksheet

```Average atomic mass worksheet 2
Name: _____________________________________
Date: _____________
1.
Isotope Name
Silver -107
Mass Number
107
Silver -109
109
a.
Find the missing percentage.
b.
Find the average atomic mass of silver.
Percentage Abundance
51.86%
2.
Isotope Name
Silicon -28
Silicon -29
Silicon -30
a.
Mass Number
Percentage Abundance
92.21%
4.70%
3.09
Silicon has three naturally occurring isotopes. Look over the data before you begin the
problem. Estimate the value of the answer before you begin the calculation. Will the
weighted average be closer to 28, 29, or 30?
b.
Find the average atomic mass of an atom of silicon.
3.
Isotope Name
Iron -54
Iron -56
Iron -57
Iron -58
a.
Mass Number
Calculate the average atomic mass of iron.
4. Titanium has five common Isotopes: 46Ti (8.0%), 47Ti (7.8%),
(5.3%). What is the average atomic mass of titanium?
5.
Percentage Abundance
5.9%
91.72%
2.10%
0.280%
48
Ti (73.4%),
49
Ti (5.5%),
50
Ti
A chemistry student’s grade is weighted. Tests are worth 50.0 %, labs are worth 25.0 %, and
homework is worth 25.0 %. A student’s test average is 85.0 %, lab average is 77.0 %, and homework
is 91.0 %.
a.
What is the students average grade?
```