The average atomic mass of boron is 10811 amu Calculate the natural abundances

The average atomic mass of boron is 10811 amu

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respectively. The average atomic mass of boron is 10.811 amu. Calculate the natural abundances of these two isotopes. PRACTICE: Which of the following statements about isotopes is TRUE? A) Isotopes of the same element don't usually have the same properties. B) An isotope of an atom with a larger number of neutrons is larger than an isotope of the same atom that contains fewer neutrons. C) Isotopes of the same element differ only in the number of electrons they contain. D) Isotopes of the same element have the same mass. E) Some elements have 3 or more naturally occurring isotopes. * This review was not prepared by your professor or school and is neither approved nor endorsed by your college or university 7
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ECU - GENERAL CHEMISTRY I - PROF. SPUCHES ECU CHEM 1150 SPUCHES EXAM 2 REVIEW* PRACTICE: Naturally occurring bromine consists of two isotopes, 79 Br and 81 Br with isotopic masses of 78.9183 and 80.9163, respectively. Given that the observed atomic mass of bromine is 79.904, calculate the percent abundance of 79 Br and 81 Br in naturally occurring bromine. SUMMARY: Empirical Formula * This review was not prepared by your professor or school and is neither approved nor endorsed by your college or university 8
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ECU - GENERAL CHEMISTRY I - PROF. SPUCHES ECU CHEM 1150 SPUCHES EXAM 2 REVIEW* PRACTICE: What is the empirical formula for the compound P 4 O 6 ? PRACTICE: Catechol is 65.4% carbon, 5.49% hydrogen, and 29.1% oxygen by mass. What is the empirical formula for catechol? (A) C 3 H 3 O (B) C 3 H 3 O 2 (C) C 6 H 6 O 2 (D) CHO 0.333 (E) None of the above * This review was not prepared by your professor or school and is neither approved nor endorsed by your college or university 9
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ECU - GENERAL CHEMISTRY I - PROF. SPUCHES ECU CHEM 1150 SPUCHES EXAM 2 REVIEW* PRACTICE: Part A: A chemist attempted to synthesize a particular compound that showed promise as a new antibiotic. If she succeeded in making and purifying the compound, then it contains only carbon, hydrogen, bromine, and oxygen. She sent a sample off for analysis, and days later the following results arrived: carbon, 34.35%; hydrogen, 1.725%; bromine, 45.65%; oxygen, 18.27% Determine the empirical formula. Part B: Because the scientist knows the compound she is trying to make, she can calculate the molar mass, assuming she synthesized the right compound. The expected molar mass is 699.9 g/mol. What is the molecular formula of the compound? * This review was not prepared by your professor or school and is neither approved nor endorsed by your college or university 10
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ECU - GENERAL CHEMISTRY I - PROF. SPUCHES ECU CHEM 1150 SPUCHES EXAM 2 REVIEW* PRACTICE: On combustion analysis, a 0.450 g sample of a chemical compound gives 0.418 g of water and 1.023 g of carbon dioxide. Assuming that the empirical formula of the compound is C x H y O z , find the values of x, y and z. PRACTICE: 2.404 g of a compound were burned in oxygen and found to produce only 3.520 g CO 2 (g), 2.564 g SO 2 (g) and 1.440 g H 2 O (l). Determine the empirical formula of the compound.
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