Example 4.7. 1 Step 1: List the known and unknown quantities and plan the problem. Step 2: Calculate. chlorine-350.7577×34.969=26.50amuchlorine-370.2423×36.966=8.957amuaverage atomic mass26.50+8.957=35.46amu. ... Step 3: Think about your result.

Use the atomic masses of each of the isotopes along with their percent abundances to calculate the average atomic mass. Change each percent abundance into decimal form by dividing by 100. Multiply this value by the atomic mass of that isotope. Add together for each isotope to get the average atomic mass.

The average atomic mass of the given sample of chlorine is 35.46 u .

Chemistry of the Living World Chlorine has two common isotopes, chlorine-35 and chlorine-37, and an atomic mass of 35.45 amu.

Copper has two isotopes, 63Cu (69.15%, mass=62.9300 amu) and 65Cu (30.85%, mass = 64.928 amu), and so the respective mole fractions are 0.6915 and 0.3085, resulting in an average atomic weight of 63.55 amu, even though there is not a single atom that weighs 63.55 amu.

The element copper has naturally occurring isotopes with mass numbers of 63 and 65. The relative abundance and atomic masses are 69.2% for a mass of 62.93amu and 30.8% for a mass of 64.93 amu.

ī 35 = 34.969 amu) 5) Naturally occurring chlorine that is put in pools is 75.53 percent ³Cl (mass and 24.47 percent "Cl (mass = 36.966 amu). Calculate the average atomic mass. 0.7870x 2.531 x=123.8044 amul 3.0399 = 24.3050.

The average atomic mass is useful because its numerical value is equal to the molar mass of the element. This in turn is useful to know how much of a solid to take when you wish to react it with some known quantity of another reagent, because weighing is typically the easiest way to quantify a substance.

Hence , the average atomic mass of chlorine is 35.5. Therefore,Option B is correct.