2. Consider the element Uranium, U. Determine which isotopes are naturally occurring. Look up the masses of each isotope in amu, and the natural abundances. Calculate the average atomic weight, and compare this to what you find in the periodic table. Given the atomic mass numbers of the isotopes, is the atomic mass number consistent with these atomic mass numbers? Why or why not? If it seems inconsistent, can you explain this apparent inconsistency?

2. Consider the element Uranium, U. Determine which isotopes are naturally occurring. Look up the masses of each isotope in amu, and the natural abundances. Calculate the average atomic weight, and compare this to what you find in the periodic table. Given the atomic mass numbers of the isotopes, is the atomic mass number consistent with these atomic mass numbers? Why or why not? If it seems inconsistent, can you explain this apparent inconsistency?

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 23Q: Reference Section 5-2 to find the atomic masses of 12C and 13C, the relative abundance of 12C and...

See similar textbooks

Similar questions

Click on the site (http://openstaxcollege.org/l/16PhetAtomMass) and select the Mix Isotopes tab, hide the Percent Composition and Average Atomic Mass boxes, and then select the element boron. Write the symbols of the isotopes of boron that are shown as naturally occurring in significant amounts. Predict the relative amounts (percentages) of these boron isotopes found in nature. Explain the reasoning behind your choice. Add isotopes to the black box to make a mixture that matches your prediction in (b). You may drag isotopes from their bins or click on More and then move the sliders to the appropriate amounts. Reveal the Percent Composition and Average Atomic Mass boxes. How well does your mixture match with your prediction? If necessary, adjust the isotope amounts to match your prediction. Select Nature’s mix of isotopes and compare it to your prediction. How well does your prediction compare with the naturally occurring mixture? Explain. If necessary, adjust your amounts to make them match Nature’s amounts as closely as possible. 21. Repeat Exercise 2.20 using an element that has three naturally occurring isotopes.
These questions concern the work of J. J. Thomson. a. From Thomsons work, which particles do you think he would feel are most important for the formation of compounds (chemical changes) and why? b. Of the remaining two subatomic particles, which do you place second in importance for forming compounds and why? c. Propose three models that explain Thomsons findings and evaluate them. To be complete you should include Thomsons findings.
Chlorine has two isotopes, Cl-35 and Cl-37. Their abundances are 75.53% and 24.47%, respectively. Assume that the only hydrogen isotope present is H-1. (a) How many different HCI molecules are possible? (b) What is the sum of the mass numbers of the two atoms in each molecule? (c) Sketch the mass spectrum for HCI if all the positive ions are obtained by removing a single electron from an HCI molecule.
Click on the site (http://openstaxcollege.org/l/16PhetAtomMass) and select the Mix Isotopes tab, hide the Percent Composition and Average Atomic Mass boxes, and then select the element boron. Write the symbols of the isotopes of boron that are shown as naturally occurring in significant amounts. Predict the relative amounts (percentages) of these boron isotopes found in nature. Explain the reasoning behind your choice. Add isotopes to the black box to make a mixture that matches your prediction in (b). You may drag isotopes from their bins or click on More and then move the sliders to the appropriate amounts. Reveal the Percent Composition and Average Atomic Mass boxes. How well does your mixture match with your prediction? If necessary, adjust the isotope amounts to match your prediction. Select Nature’s mix of isotopes and compare it to your prediction. How well does your prediction compare with the naturally occurring mixture? Explain. If necessary, adjust your amounts to make them match Nature’s amounts as closely as possible.
The average atomic masses of some elements may vary, depending upon the sources of their ores. Naturally occurring boron consists of two isotopes with accurately known masses ( 10B, 10.0129 amu and 11B, 11.0931 amu). The actual atomic mass of boron can vary from 10.807 to 10.8 19, depending on whether the mineral source is from Turkey or the United States. Calculate the percent abundances leading to the two values of the average atomic masses of boron from these two countries.
A cube of sodium has length 1.25 in. How many atoms are in that cube? (Note: dNa=0.968g/cm3.)
A gaseous binary compound has a vapor density that is 1.94 times that of oxygen at the same temperature and pressure. When 1.39 g of the gas is burned in an excess of oxygen, 1.21 g water is formed, removing all the hydrogen originally present. (a) Estimate the molecular mass of the gaseous compound. (b) How many hydrogen atoms are there in a molecule of the compound? (c) What is the maximum possible value of the atomic mass of the second element in the compound? (d) Are other values possible for the atomic mass of the second element? Use a table of atomic masses to identify the element that best fits the data. (e) What is the molecular formula of the compound?
Indium oxide contains 4.784 g of indium for every 1.000 g of oxygen. In 1869, when Mendeleev first presented his version of the periodic table, he proposed the formula In2O3 for indium oxide. Before that time it was thought that the formula was InO. What values for the atomic mass of indium are obtained using these two formulas? Assume that oxygen has an atomic mass of 16.00.
A mass spectrometer determines isotopic masses to eight or nine significant digits. What limits the atomic mass of carbon to only five significant digits?
There are 1.699 1022 atoms in 1.000 g of chlorine. Assume that chlorine atoms are spheres of radius 0.99 and that they are lined up side by side in a 0.5-g sample. How many miles in length is the line of chlorine atoms in the sample?
Average atomic masses listed by JUPAC are based on a study of experimental results. Bromine has two isotopes 79Br and 81Br, whose masses (78.9 183 and 80.9 163 amu) and abundances (50.69% and 49.3 1%) were determined in earlier experiments. Calculate the average atomic mass of bromine based on these experiments.
Europium has two stable isotopes, 151Eu and 153Eu, with masses of 150.9197 u and 152.9212 u, respectively. Calculate the percent abundances of these isotopes of europium.