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Problem 22.94
Which of the group 4A elements have allotropes with the diamond structure? Which have metallic allotropes? How does the variation in the structure of the group 4A elements illustrate how metallic character varies down a periodic group?
Problem 22.95
Give an example of an ionic carbide. What is the oxidation state of carbon in this substance?
Problem 22.96
Why are CO and CN– so toxic to humans?
Problem 22.99
Using the shorthand notation of Figure 22.9, draw the structure of the silicate anion in:
(a) K4SiO4 (b) Ag10Si4O13
What is the relationship between the charge on the anion and the number of terminal O atoms?
Problem 23
The following pictures represent structures of the hydrides of four second-row elements:
(1)
(2)
(3)
(4)
(c) Which compounds yield H2 gas when they are mixed together?
Problem 24
In the following pictures of oxides, red spheres represent O atoms or ions, and green spheres represent atoms or ions of a second- or third-row element in its highest oxidation state.
(1)
(2)
(3)
(b) Identify each oxide as ionic or covalent.
Problem 26
Look at the location of elements A, B, C, and D in the following periodic table:
(a) Write the formula of the oxide that has each of these elements in its highest oxidation state.
Problem 30
The following models represent the structures of binary
oxides of second- and third-row elements in their highest
oxidation states:
(a) Identify the non-oxygen atom in each case, and write the molecular formula for each oxide.
- Which element in each of the following pairs has the higher ionization energy? (a) As or Cl (b) Mg or Ba
Problem 32
- Arrange the following elements in order of increasing ionization energy: (a) N (b) Ca (c) Rb (d) Se.
Problem 33
- Which element in each of the following pairs has the larger atomic radius? (a) Sn or P (b) Ge or Br
Problem 34
- Arrange the following elements in order of increasing atomic radius: (a) Rb (b) F (c) Sb (d) S.
Problem 35
- Which element in each of the following pairs has the higher electronegativity? (a) Sb or I (b) P or Sb
Problem 36
- Arrange the following elements in order of increasing electronegativity: (a) Sr (b) Cl (c) Sn (d) Ge.
Problem 37
- Which element in each of the following pairs has more metallic character? (a) Bi or As
Problem 38
- Which element in each of the following pairs has more nonmetallic character? (b) Br or As
Problem 39
- Which compound in each of the following pairs is more covalent? (a) CaO or NO (b) NH3 or KH (c) SnO2 or SiO2
Problem 41
- Which of the following compounds are molecular, and which have an extended three-dimensional structure? (a) B2H6 (b) KAlSi3O8 (c) SO3 (d) GeCl4
Problem 42
- Consider the elements C, Se, B, Sn, and Cl. Identify which of these elements: (a) Has a maximum oxidation state of +6, (b) Has the largest atomic radius, (c) Is the most electronegative.
Problem 44
- Consider the elements N, Si, Al, S, and F. Identify which of these elements: (a) Has the highest ionization energy; (b) Has the most metallic character; (d) Forms a 2- anion.
Problem 45
- At ordinary temperatures, sulfur exists as S8 but oxygen exists as O2. Explain.
Problem 48
- Carbon, nitrogen, and oxygen form π bonds, but fluorine does not. Explain.
Problem 49
Problem 51
Consider the elements Mn, Al, C, S, and Si. Which element forms the strongest π bonds?
- Write a balanced equation for the synthesis of hydrogen using each of the following starting materials: (b) C, (c) CH4, (d) H2O.
Problem 52
Problem 53a,c
Complete and balance the equation for each of the following reactions.
a. Fe(s) + H+(aq) →
c. Al(s)+ H+(aq) →
- Calcium hydride is a convenient, portable source of hydrogen that is used, among other things, to inflate weather balloons. If the reaction of CaH2 with water is used to inflate a balloon with 2.0 * 10^5 L of H2 gas at 25 °C and 1.00 atm pressure, how many kilograms of CaH2 are needed?
Problem 54
- The hydrogen-filled dirigible Hindenburg had a volume of 1.99 * 108 L. If the hydrogen used was produced by the reaction of carbon with steam, how many kilograms of carbon would have been needed to produce enough hydrogen to fill the dirigible at 20 °C and 740 mm pressure?
Problem 55
- Write the chemical formula of a compound that contains hydrogen and each of the following elements. Which of these compounds are ionic, and which are covalent? (a) K (b) S
Problem 57
- In the following compound, is hydrogen present as H+, H-, or a covalently bound H atom? (b) PH3
Problem 58
- In the following compounds, is hydrogen present as H+, H-, or a covalently bound H atom? (b) RbH (d) GeH4
Problem 59