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Average atomic mass and isotope abundance

This type of question, asked 4 times: 10 May 2023 S1, 19 Apr 2026 S2, 20 Apr 2026 S1, 14 May 2026 S2. All 4 questions below, oldest first.

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  1. Question 1

    10 May 2023 S1

    96
    Chlorine exists in two isotopic forms 35Cl^{35}\text{Cl}, 37Cl^{37}\text{Cl}. If average atomic mass of chlorine is 35.5, what is the percentage abundance of these isotopes respectively?

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  2. Question 2

    19 Apr 2026 S2

    1
    Chlorine has two isotopes Cl37\mathrm{Cl^{37}} and Cl35\mathrm{Cl^{35}} with percentage abundance of 25%25\% and 75%75\% respectively. Find average atomic mass of chlorine ?

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  3. Question 3

    20 Apr 2026 S1

    1
    What is average atomic mass of chlorine if its two isotopes Cl35\mathrm{Cl^{35}} and Cl37\mathrm{Cl^{37}} exists in relative abundance of 75%75\% and 25%25\% respectively ?

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  4. Question 4

    14 May 2026 S2

    1
    An element has two isotopes of mass numbers 6565 and 6767 with abundances of 25%25\% and 75%75\% respectively. Then the average atomic mass of the element is

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