Average Atomic Mass Practice Problems

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.
What is the average mass of this element?

• 74.92 amu

• 24.97 amu

• 75.01 amu

• 74.51 amu

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?

• 41.97 amu

• 42.19 amu

• 10.43 amu

• 40.04 amu

Tags

NGSS.MS-PS1-2

Compute the average atomic mass for silicon:

• 27.977

• 28.09

• 28.976

• The average mass cannot be determined from provided information.

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?

• 32

• 33

• 34

• no way to know

What is the atomic mass of Sodium?

• 11

• 22.990

• 33.990

• 11.990

What is the atomic mass of Gold?

• 79

• 196.97

• 79.97

• 275

What is the atomic mass of "F"

• 9

• 18

• 17

• 19

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?

• 36.33 amu

• 37.00 amu

• 12.11 amu

• impossible to tell

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

• 2 amu

• 3 amu

• 4 amu

• 5 amu

Calculate the average atomic mass of silver.

• 106.38649amu

• 111.91896amu

• 107.8677amu

• 121