8. Element Xhas two isotopes. If 72.0% of the element has an atomic mass of 84.9(72.0 + 84.9) x (28.0 + 87.0)atomic mass units, and 28.0% of the element has an atomic mass of 87.0 atomicmass units, the average atomic mass of element X is equal to which of thefollowing?72.0 x 84.928.0 x 87.0100100(72.0 x 84.9) + (28.0 × 87.0)(72.0 – 84.9) x (28.0 + 87.0)CLEAR ALL

Element X has two isotopes. If 72.0% of the element has an atomic mass of 84.9 atomic mass units, and 28.0% of the element has an atomic mass of 87.0 atomic (72.0 + 84.9) × (28.0 + 87.0) mass units, the average atomic mass of element x is equal to which of the Following? 72.0 x 84.9 28.0 x 87.0 100 100 (72.0 × 84.9) + (28.0 × 87.0) (72.0 – 84.9) × (28.0 + 87.0) CLEAR ALL

Element X has two isotopes. If 72.0% of the element has an atomic mass of 84.9 atomic mass units, and 28.0% of the element has an atomic mass of 87.0 atomic (72.0 + 84.9) × (28.0 + 87.0) mass units, the average atomic mass of element x is equal to which of the Following? 72.0 x 84.9 28.0 x 87.0 100 100 (72.0 × 84.9) + (28.0 × 87.0) (72.0 – 84.9) × (28.0 + 87.0) CLEAR ALL

Chemistry: An Atoms First Approach

2nd Edition

ISBN:9781305079243

Author:Steven S. Zumdahl, Susan A. Zumdahl

Publisher:Steven S. Zumdahl, Susan A. Zumdahl

Chapter5: Stoichiometry

Section: Chapter Questions

Problem 37E: An element consists of 1.40% of an isotope with mass 203.973 u, 24.10% of an isotope with mass...

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Mass spectrometric analysis showed that there are four isotopes of an unknown element having the following masses and abundances: Three elements in the periodic table that have atomic weights near these values are lanthanum (La), atomic number 57, atomic weight 138.9055; cerium (Ce), atomic number 58, atomic weight 140.115; and praseodymium (Pr), atomic number 59, atomic weight 140.9076. Using the data above, calculate the atomic weight, and identify the element if possible.
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The element europium exists in nature as two isotopes: 151Eu has a mass of 150.9196 u and 153Eu has a mass of 152.9209 u. The average atomic mass of europium is 151.96 u. Calculate the relative abundance of the two europium isotopes.