Page 111 - Theory and Problems of BEGINNING CHEMISTRY

100 INORGANIC NOMENCLATURE [CHAP. 6

6.50. Write formulas for each of the following compounds: (a) calcium hydrogen carbonate, (b) disodium
hydrogen phosphate, (c) sodium dihydrogen phosphate, and (d) calcium dihydrogen phosphate.
Ans. (a) Ca(HCO 3 ) 2 (the single charge on one HCO 3 ion is not sufficient to balance the 2+ charge on Ca ;two
2+
−
anions are necessary) (b)Na 2 HPO 4 (c) NaH 2 PO 4 (d) Ca(H 2 PO 4 ) 2
[The same prefix is used to denote two atoms in (b), (c), and (d) as in nonmetal-nonmetal compounds.]

HYDRATES
6.51. Name the following compound, and state how many hydrogen atoms it contains per formula unit:
Ni(C 2 H 3 O 2 ) 2 ·4H 2 O
Ans. Nickel(II) acetate tetrahydrate. It contains 14 H atoms per formula unit.

6.52. Write formulas for barium dihydrogen hypophosphite and barium dihydrogen hypophosphite
monohydrate.

Ans. Ba(H 2 PO 2 ) 2 and Ba(H 2 PO 2 ) 2 ·H 2 O

Supplementary Problems

6.53. Name (a)H ,(b)H ,(c) NaH, and (d) BeH 2 .
+
−
Ans. (a) Hydrogen ion (b) Hydride ion (c) Sodium hydride (d) Beryllium hydride

6.54. Explain why the formula for mercury(I) ion is Hg 2 2+ rather than Hg .
+
Ans. The actual formula shows that the two mercury atoms are covalently bonded.
6.55. Explain why mercury(I) ion, Hg 2 , has the Roman numeral I in it.
2+
Ans. The average charge on the two Hg atoms is 1+. (See Sec. 14.2.)

6.56. Write formulas for each of the following compounds: (a) ammonium nitrate, (b) mercury(I) cyanide, and (c) uranyl
carbonate.
Ans. (a)NH 4 NO 3 (from Table 6-3) (b)Hg 2 (CN) 2 (from Tables 6-3 and 6-6) (c)UO 2 CO 3 (from Table 6-3)

6.57. Write a formula for each of the following compounds: (a) diphosphorus pentasulfide, (b) iodine heptafluoride, and
(c) dinitrogen monoxide.
Ans. (a)P 2 S 5 (b)IF 7 (one of the few times the prefix hepta- is used) (c)N 2 O

6.58. State the meaning of each of the following terms: (a) per-,(b) hypo-,(c) hydro-,(d) hydrogen (as part of an ion).
−
Ans. (a) Per- means “more oxygen atoms.” For example, the perchlorate ion (ClO 4 ) has more oxygen atoms
than does the chlorate ion (ClO 3 ). (b) Hypo- means “fewer oxygen atoms.” For example, the hypochlorite
−
−
ion (ClO ) has fewer oxygen atoms than does the chlorite ion (ClO 2 ). (c) Hydro- means “no oxygen
−
atoms.” For example, hydrochloric acid (HCl) has no oxygen atoms, in contrast to chloric acid (HClO 3 ).
(d) Hydrogen signifies an acid salt, such as NaHS—sodium hydrogen sulfide.
6.59. What relationship is there in the meaning of the prefix per- when used with an oxyanion and when used in peroxide?
Ans. In both cases, it means “one more oxygen atom.”

6.60. What are the differences among the following questions? (a) What is the formula of the compound of sulfur and
calcium? (b) What is the formula of the compound of Ca 2+ and S ?(c) What is the formula for calcium sulfide?
2−