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문제 31a
Write the correct symbol, with both superscript and subscript, for each of the following. Use the list of elements in the front inside cover as needed: (a) the isotope of platinum that contains 118 neutrons
문제 31b,c
Write the correct symbol, with both superscript and subscript, for each of the following. Use the list of elements in the front inside cover as needed: (b) the isotope of krypton with mass number 84 (c) the isotope of rhenium with mass number 187
문제 31d
Write the correct symbol, with both superscript and subscript, for each of the following. Use the list of elements in the front inside cover as needed: (d) the isotope of magnesium that has an equal number of protons and neutrons.
- Without doing any detailed calculations (but using a periodic table to give atomic weights), rank the following samples in order of increasing numbers of atoms: 0.2 mol PCl5 molecules, 80 g Fe2O3, 3.0 3 1023 CO molecules.
문제 32
문제 33a
(a) What isotope is used as the standard in establishing the atomic mass scale?
문제 33b
(b) The atomic weight of boron is reported as 10.81, yet no atom of boron has the mass of 10.81 u. Explain.
문제 34a
(a) What is the mass in u of a carbon-12 atom?
문제 34b
(b) Why is the atomic weight of carbon reported as 12.011 in the table of elements and the periodic table in the front inside cover of this text?
문제 35
Only two isotopes of copper occur naturally: 63Cu (atomic mass = 62.9296 amu; abundance 69.17%) 65Cu (atomic mass = 64.9278 amu; abundance 30.83%). Calculate the atomic weight (average atomic mass) of copper.
문제 36
Rubidium has two naturally occurring isotopes, rubidium-85 (atomic mass = 84.9118 amu; abundance = 72.15%) and rubidium-87 (atomic mass = 86.9092 amu; abundance = 27.85%). Calculate the atomic weight of rubidium
- (b) What are the labels on the axes of a mass spectrum? (c) To measure the mass spectrum of an atom, the atom must first lose one or more electrons. Which ion would you expect to be deflected more by the same setting of the electric and magnetic fields, a Cl+ or a Cl2+ ion?
문제 37
문제 37a
(a) Thomson's cathode-ray tube (Figure 2.4) and the mass spectrometer (Figure 2.11) both involve the use of electric or magnetic fields to deflect charged particles. What are the charged particles involved in each of these experiments?
문제 38a
Consider the mass spectrometer shown in Figure 2.11. Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (a) The paths of neutral (uncharged) atoms are not affected by the magnet.
문제 38b
Consider the mass spectrometer shown in Figure 2.11. Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (b) The height of each peak in the mass spectrum is inversely proportional to the mass of that isotope.
- Naturally occurring lead has the following isotopic abundances: Isotope Abundance (%) Atomic mass (u) 204Pb 1.4 203.9730, 206Pb 24.1 205.9744, 207Pb 22.1 206.9759, 208Pb 52.4 207.9766. (a) What is the average atomic mass of Pb? (b) Sketch the mass spectrum of Pb.
문제 39
문제 40a
Massspectrometry is more often applied to molecules than to atoms. We will see in Chapter 3 that the molecular weight of a molecule is the sum of the atomic weights of the atoms in the molecule. The mass spectrum of H2 is taken under conditions that prevent decomposition into H atoms. The two naturally occurring isotopes of hydrogen are 1H (atomic mass = 1.00783 amu; abundance 99.9885%) and 2H (atomic mass = 2.01410; abundance 0.0115%). (a) How many peaks will the mass spectrum have?
문제 40c
Massspectrometry is more often applied to molecules than to atoms. We will see in Chapter 3 that the molecular weight of a molecule is the sum of the atomic weights of the atoms in the molecule. The mass spectrum of H2 is taken under conditions that prevent decomposition into H atoms. The two naturally occurring isotopes of hydrogen are 1H (atomic mass = 1.00783 amu; abundance 99.9885%) and 2H (atomic mass = 2.01410; abundance 0.0115%). (c) Which peak will be the largest, and which the smallest?
문제 41
For each of the following elements, write its chemical symbol, locate it in the periodic table, give its atomic number, and indicate whether it is a metal, metalloid, or nonmetal: (a) radon (b) tellurium (c) cadmium (d) chromium (e) barium (f) selenium (g) arsenic.
- Locate each of the following elements in the periodic table; give its name and atomic number, and indicate whether it is a metal, metalloid, or nonmetal: (a) Hg (b) At (c) Mo (d) W (e) Sn (f) V (g) K.
문제 42
문제 43
For each of the following elements, write its chemical symbol, determine the name of the group to which it belongs (Table 2.3), and indicate whether it is a metal, metalloid, or nonmetal: (a) polonium (b) strontium (c) neon (d) rubidium (e) sulfur.
- The elements of Group 14 show an interesting change in properties moving down the group. Give the name and chemical symbol of each element in the group and label it as a nonmetal, metalloid, or metal.
문제 44
문제 45b
The structural formulas of the compounds n-butane and isobutane are shown below. (b) Determine the empirical formula of each.
문제 45c
The structural formulas of the compounds n-butane and isobutane are shown below. (c) Which formulas—empirical, molecular, or structural—allow you determine these are different compounds?
문제 46a
Ball-and-stick representations of benzene, a colorless liquid often used in organic chemistry reactions, and acetylene, a gas used as a fuel for high-temperature welding, are shown below. (a) Determine the molecular formula of each.
문제 47a
What are the molecular and empirical formulas for each of the following compounds? Write the molecular formula for the following compound.
문제 48
Two substances have the same molecular and empirical formulas. Does this mean that they must be the same compound?
문제 49a
Write the empirical formula corresponding to each of the following molecular formulas: (a) Al2Br6
문제 49b
Write the empirical formula corresponding to each of the following molecular formulas: (b) C8H10
문제 49c
Write the empirical formula corresponding to each of the following molecular formulas: (c) C4H8O2
문제 49d,e,f
Write the empirical formula corresponding to each of the following molecular formulas: (d) P4O10 (e) C6H4Cl2 (f) B3N3H6.