Chapter 5 – Practice Problems (Masses of Atoms and Molecules)
- Define atomic mass unit. What is its abbreviation?
- Define atomic mass. What is its unit?
- Estimate the mass, in whole numbers, of each isotope.
- a. hydrogen-1
- b. hydrogen-3
- c. iron-56
- Estimate the mass, in whole numbers, of each isotope.
- a. phosphorus-31
- b. carbon-14
- c. americium-241
- Determine the atomic mass of each element, given the isotopic composition.
- a. lithium, which is 92.4% lithium-7 (mass 7.016 u) and 7.60% lithium-6 (mass 6.015 u)
- b. oxygen, which is 99.76% oxygen-16 (mass 15.995 u), 0.038% oxygen-17 (mass 16.999 u), and 0.205% oxygen-18 (mass 17.999 u)
- Determine the atomic mass of each element, given the isotopic composition.
- a. neon, which is 90.48% neon-20 (mass 19.992 u), 0.27% neon-21 (mass 20.994 u), and 9.25% neon-22 (mass 21.991 u)
- b. uranium, which is 99.27% uranium-238 (mass 238.051 u) and 0.720% uranium-235 (mass 235.044 u)
- How far off would your answer be from Exercise 5a if you used whole-number masses for individual isotopes of lithium?
- How far off would your answer be from Exercise 6b if you used whole-number masses for individual isotopes of uranium?
- a. What is the atomic mass of an oxygen atom?
- b. What is the molecular mass of oxygen in its elemental form?
- c. What is the atomic mass of bromine?
- d. What is the molecular mass of bromine in its elemental form?
- Determine the mass of each substance.
- a. F2
- b. CO
- c. CO2
- Determine the mass of each substance.
- a. Kr
- b. KrF4
- c. PF5
- Determine the mass of each substance.
- a. Na
- b. B2O3
- c. S2Cl2
- Determine the mass of each substance.
- a. IBr3
- b. N2O5
- c. CCl4
- Determine the mass of each substance.
- a. GeO2
- b. IF3
- c. XeF6
- Determine the mass of each substance.
- a. NO
- b. N2O4
- c. Ca
