Chem 065 - Introductory General Chemistry » Winter 2024 » Practice Isotopes

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Question #1
A fictional element named Nivadium is found to have three naturally occurring isotopes with the natural abundances shown here: MASS (amu) ---- ABUNDANCE 22.1760 ---- 45.00% 23.1847 ---- 45.00% 24.1934 ---- 10.00% The calculated atomic mass of Nivadium is:
A.   none of these
B.   7.61 amu
C.   22.83 amu
D.   23.18 amu
E.   69.55 amu
Question #2
A fictional element has two naturally occurring isotopes with the natural abundances shown here: ISOTOPE ---- ABUNDANCE 18 ---- 40.0% 20 ---- 60.0% Which statement is TRUE for this element?
A.   The atomic mass would be exactly 19.
B.   The atomic mass would be closer to 18 than to 20.
C.   The atomic mass would be greater than 20.
D.   The atomic mass would be closer to 20 than to 18.
E.   The atomic mass would be less than 18.
Question #3
A fictional element has two naturally occurring isotopes with the natural abundances shown here: ISOTOPE ---- ABUNDANCE 16 ---- 50.0% 18 ---- 50.0% Which statement is TRUE for this element?
A.   The atomic mass would be 18.
B.   The atomic mass would be 17.
C.   The atomic mass would be less than 16.
D.   The atomic mass would be 16.
E.   The atomic mass would be more than 18.
Question #4
A fictional element has two isotopes, each making up 50% of the population. Isotope 1 has a mass of 80.0 amu, Isotope 2 has a mass of 85.0 amu. Calculate the atomic mass of the fictional element.
A.   none of these
B.   165 amu
C.   82.5 amu
D.   42.5 amu

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