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- Match the descriptions (a)–(e) with the following terms: atomic weight, atomic mass, mass number, atomic number, molar mass. (a) The mass of a specific atom such as one atom of 13C (b) The quantity determined by the number of protons in an element. (c) The number of grams in 1 mol of an element (d) The number of protons and neutrons in an element (e) The weighted average of the isotopic masses of an element's naturally occurring isotopes
Problem 114
- Label the following statements as true or false. (a) The atomic weight and the atomic number of an element have the same numerical value. (b) The molar mass in grams for an element and the atomic weight have the same numerical value.
Problem 115
- Copper has two naturally occurring isotopes, including 65Cu. Look at the periodic table and tell whether the second isotope is 63Cu or 66Cu.
Problem 116
Problem 119
Naturally occurring silver consists of two isotopes: 107^Ag (51.84%) with an isotopic mass of 106.9051 and 109^Ag (48.16%) with an isotopic mass of 108.9048. What is the atomic weight of silver? Check your answer in a periodic table.
Problem 120
Magnesium has three naturally occurring isotopes: 24Mg (23.985) with 78.99% abundance, 25Mg (24.986) with 10.00% abundance, and a third with 11.01% abundance. Look up the atomic weight of magnesium, and then calculate the mass of the third isotope.
- A sample of naturally occurring silicon consists of 28^Si (27.9769), 29^Si (28.9765), and 30^Si (29.9738). If the atomic weight of silicon is 28.0855 and the natural abundance of 29^Si is 4.68%, what are the natural abundances of 28^Si and 30^Si?
Problem 121
- Copper metal has two naturally occurring isotopes: copper-63 (69.15%; isotopic mass = 62.93) and copper-65 (30.85%; isotopic mass 64.93). Calculate the atomic weight of copper, and check your answer in the periodic table.
Problem 122
- Germanium has five naturally occurring isotopes: 70^Ge, 20.5%, 69.924; 72^Ge, 27.4%, 71.922; 73^Ge, 7.8%, 72.923; 74^Ge, 36.5%, 73.921; and 76^Ge, 7.8%, 75.921. What is the atomic weight of germanium?
Problem 123
- What is the mass in grams of each of the following samples? (a) 1.505 mol of Ti (b) 0.337 mol of Na (c) 2.583 mol of U
Problem 124
- If the atomic weight of an element is x, what is the mass in grams of 6.02 x 10^23 atoms of the element? How does your answer compare numerically with the atomic weight of element x?
Problem 126
- If the atomic weight of an element is x, what is the mass in grams of 3.17 * 1020 atoms of the element?
Problem 127
- If 6.02 * 1023 atoms of element Y have a mass of 83.80 g, what is the identity of Y?
Problem 128
- If 4.61 * 10^21 atoms of element Z have a mass of 0.815 g, what is the identity of Z?
Problem 129
Problem 130a
Refer to Figure 2.10 showing a schematic illustration of a mass spectrometer. (a) What is the purpose of bombarding the gaseous atoms with an electron beam?
Problem 130b
Refer to Figure 2.10 showing a schematic illustration of a mass spectrometer. (b) Compare two ions with a +1 charge traveling through the curved, evacuated tube in the mass spectrometer. Will a heavier ion or lighter ion be deflected to a greater degree by the magnetic field?
- Use the data from the mass spectrum of a sample of an element to calculate the element's atomic weight. Identify the element.
Problem 132
- How many protons and electrons are in each of the following ions? (a) Be2+ b) Rb+ c) Se2- (d) Au3+
Problem 138
- What is the identity of the element X in the following ions? (a) X2+, a cation that has 36 electrons (b) X-, an anion that has 36 electrons
Problem 139
Problem 141
Lactic acid, a compound found both in sour milk and in tired muscles, has the structure shown. What is its chemical formula?
Problem 146a
Give systematic names for the following binary compounds: (a) CsF
Problem 146b
Give systematic names for the following binary compounds: (b) K2O
Problem 146c
Give systematic names for the following binary compounds: (c) CuO
Problem 147a
Give systematic names for the following binary compounds: (a) BaS
Problem 147b
Give systematic names for the following binary compounds: (b) BeBr2
Problem 147c
Give systematic names for the following binary compounds: (c) FeCl3
Problem 149
Write formulas for the following binary compounds: (a) Vanadium(III) chloride (b) Manganese(IV) oxide (c) Copper(II) sulfide (d) Aluminum oxide
Problem 150
Write formulas for the following compounds: (a) Calcium acetate (b) Iron(II) cyanide (c) Sodium dichromate (d) Chromium(III) sulfate (e) Mercury(II) perchlorate
Problem 151
Write formulas for the following compounds: (a) Lithium phosphate (b) Magnesium hydrogen sulfate (c) Manganese(II) nitrate (d) Chromium(III) sulfate
Problem 152a
Give systematic names for the following compounds: (a) Ca(ClO)2
Problem 152b
Give systematic names for the following compounds: (b) Ag2S2O3