Average Atomic Mass Calculation Quiz

Questions and Answers

What is the average atomic mass for Li if 7.5% of Li atoms are 6Li (mass 6.0151223 amu) and 92.5% are 7Li (mass 7.0160041 amu)?

6.94

What is the average atomic mass for B if 19.9% of B atoms are 10B (mass 10.0129371 amu) and 80.1% are 11B (mass 11.0093055 amu)?

10.81

What is the average atomic mass for Cl if 75.78% of Cl atoms are 35Cl (mass 34.96885271 amu) and 24.22% are 37Cl (mass 36.96590260 amu)?

35.45

What is the average atomic mass for Mg if 78.99% of Mg atoms are 24Mg (mass 23.9850419 amu), 10.00% are 25Mg (mass 24.9858370 amu), and 11.01% are 26Mg (mass 25.9825930 amu)?

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Study Notes

Average Atomic Mass Calculation

Average atomic mass is calculated using the abundance and mass of isotopes.
Formula: ((\text{abundance}_1 \times \text{mass}_1 + \text{abundance}_2 \times \text{mass}_2 + ... ) / 100)

Lithium (Li)

Isotopes: 6Li (7.5% abundance, 6.0151223 amu) and 7Li (92.5% abundance, 7.0160041 amu)
Calculation:
- ( (7.5 \times 6.0151223) + (92.5 \times 7.0160041) / 100 = 6.94 ) amu
Result: Average atomic mass of Li = 6.94 amu

Boron (B)

Isotopes: 10B (19.9% abundance, 10.0129371 amu) and 11B (80.1% abundance, 11.0093055 amu)
Calculation:
- ( (19.9 \times 10.0129371) + (80.1 \times 11.0093055) / 100 = 10.81 ) amu
Result: Average atomic mass of B = 10.81 amu

Chlorine (Cl)

Isotopes: 35Cl (75.78% abundance, 34.96885271 amu) and 37Cl (24.22% abundance, 36.96590260 amu)
Calculation:
- ( (75.78 \times 34.96885271) + (24.22 \times 36.965902060) / 100 = 35.45 ) amu
Result: Average atomic mass of Cl = 35.45 amu

Magnesium (Mg)

Isotopes: 24Mg (78.99% abundance, 23.9850419 amu), 25Mg (10.00% abundance, 24.9858370 amu), and 26Mg (11.01% abundance, 25.9825930 amu)
Calculation:
- ( (78.99 \times 23.9850419) + (10.00 \times 24.9858370) + (11.01 \times 25.9825930) / 100 = 24.3 ) amu
Result: Average atomic mass of Mg = 24.3 amu

Description

Test your knowledge on calculating average atomic mass using isotope abundance. This quiz covers Lithium, Boron, and Chlorine, providing insights into the isotopic composition of these elements. Challenge yourself to apply the formula and understand the concepts behind atomic mass.