Average Atomic Mass

The element copper has naturally occurring isotopes the first is 62.93amu at 69.2% abundance and the second is 64.93amu at 30.8% abundance. What is the average atomic mass of copper?

• 63.55 amu

• 63.54 amu

• 63 amu

• 64 amu

Calculate the average atomic mass of sulfur if 95.00% of all sulfur atoms have a mass of 31.972 amu, 0.76% have a mass of 32.971 amu and 4.22% have a mass of 33.967 amu.

• 32.05 amu

• 32.06 amu

• 33 amu

• 34 amu

Naturally occurring isotopes of strontium are: 0.56% are Sr-84, 9.86% are Sr-86, 7.00% are Sr-87 and 82.58% are Sr-88. What is the average atomic mass?

• 87.71 amu

• 87 amu

• 84

• 86

Potassium is an alkali metal that is one of the electrolytes needed by the human body to conduct nerve impulses. The majority of potassium (93.26%) occurs as potassium-39. The rest is either potassium-40 (0.01%) or potassium-41 (6.73%).

• 39.13 amu

• 40 amu

• 38 amu

• 93.31 amu

Zirconium is an element that makes up the cubic zirconia crystal that is commonly used as a cheap replacement for diamond. Zirconium has the following naturally occurring isotopes:

• 91.21 amu

• 92 amu

• 19.21amu

• 93 amu

Calcium is a metal that is part of bone. It has several naturally-occurring isotopes. Calculate the average atomic mass.

• 40.07 amu

• 40.08 amu

• 40 amu

• 41 amu

Tungsten is a metal found in the inner filaments of incandescent light bulbs. It has five naturally- occurring isotopes. Calculate the average atomic mass.

• 183.84 amu

• 183 amu

• 183.9 amu

• 183.85 amu

There is more hydrogen present in the universe than any other element. 99.99% of all hydrogen is the hydrogen-1 isotope. The other 0.01% is hydrogen-2, also called deuterium.

• 1.0078 amu

• 1.0001 amu

• 1.0199 amu

• 2 amu