High School Chemistry - Problem Drill 08: Naming Chemical Compounds

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1 High School Chemistry - Problem Drill 08: Naming Chemical Compounds No. 1 of Which of the following is correct for FeO? (A) Iron monoxide (B) Iron oxide (C) Iron (II) oxide (D) Iron (III) oxide (E) Iron (II) monoxide Prefixes aren t used in ionic compounds. Iron is a multivalent metal and Roman numerals are used to indicate charge. C. Correct! The -2 charge of the oxide is balanced by the +2 charge of the iron cation. The -2 charge of the oxide is balanced by a +2 charge, not a +3 charge. Prefixes aren t used in ionic compounds. This is a binary ionic compound. Iron is a multivalent metal and needs roman numerals to indicate the charge. O -2 is oxide There is 1 oxide ion, therefore there is a total negative charge of -2. Therefore there needs to be a total positive charge of +2. There is one iron cation. Therefore it is +2. Iron (II) oxide The correct answer is (C).

2 No. 2 of Which of the following is the correct name for H 2 S? (A) Hydrosulfuric acid (B) Hydrosulfurous acid (C) Sulfuric acid (D) Sulfurous acid (E) Sulfur acid A. Correct! Hydro acids end with ic. Hydro acids end with ic. Acids without oxygen are hydro acids. Acids without oxygen are hydro acids. Acids without oxygen are hydro ic acids. This is an acid that does not contain oxygen. Use hydro ic acid for this acid. S is sulfur H 2 S is hydrosulfuric acid. The correct answer is (A).

3 No. 3 of Which of the following is correct for Cu(NO 3 ) 2? (A) Copper nitrate (B) Copper nitrite (C) Copper nitride (D) Copper (II) nitrate (E) Copper (I) nitrite Copper is a multivalent metal and needs Roman numerals to indicate charge. B. Inorrect! Copper is a multivalent metal and needs Roman numerals to indicate charge. The anion is nitrate, not nitrite. Copper is a multivalent metal and needs Roman numerals to indicate charge. Don t change the ending of a polyatomic ion. D. Correct! The two -1 anions are balanced with a +2 charge for the cation. The two -1 anions are balanced with a +2 charge for the cation, not a +3 charge. Cu is copper, which is multivalent metal and needs roman numerals to indicate the charge. The polyatomic anion is nitrate and there are two of them. There is a total negative charge of -2. There must be a total positive charge of +2 and the one copper atom carries that total positive charge. Copper (II) nitrate. The correct answer is (D).

4 No. 4 of Which of the following is correct for P 2 O 5? (A) Diphosphorous pentaoxide (B) Phosphorous oxide (C) Phosphorous pentaoxide (D) Phosphate (E) Biphosphorous pentaoxide A. Correct! You used prefixes correctly. You need to use prefixes to indicate the number of atoms in covalent molecules. The only time the first element s prefix isn t used is when it is mono. This isn t a polyatomic ion, it s a covalent molecule. The prefix for 2 in covalent compounds is di. Both of these elements are non-metals. This is a binary covalent compound. Prefixes are used to indicate subscripts and -ide is used at the end of the second word. P 2 is diphosphorous O 5 is pentaoxide Diphosphorous pentaoxide The correct answer is (A).

5 No. 5 of Which of the following is correct for HNO 3? (A) Hydronitric acid (B) Hydronitrous acid (C) Nitric acid (D) Nitrous acid (E) Hydronitrogen acid Acids containing oxygen don t use hydro Acids containing oxygen don t use hydro C. Correct! The ate ion forms the ic acid. The ate ion forms ic acid. Acids containing oxygen don t use hydro This is an acid that contains oxygen. NO 3-1 is nitrate -ate polyatomic acids form -ic acids The correct answer is (C).

6 No. 6 of Which of the following is correct for Mg(OH) 2? (A) Magnesium oxygen hydride (B) Magnesium hydroxide (C) Magnesium dihydroxide (D) Magnesium dioxide (E) Magnesium bihydroxide Name the anion as a polyatomic ion. B. Correct! The anion is hydroxide Don t use prefixes with ionic compounds. Don t use prefixes with ionic compounds. Don t use prefixes with ionic compounds. Di is the prefix used for 2 when prefixes are used. This is a polyatomic ionic compound. Mg is magnesium and OH is hydroxide. Magnesium hydroxide. The correct answer is (B).

7 No. 7 of Which of the following is HClO? (A) Hydrochloric acid (B) Hydrochlorous acid (C) Hypochloric acid (D) Hypochlorous acid (E) Chlorous acid Hydro acids don t contain oxygen. Hydro acids don t contain oxygen. ite anions become ous acids. D. Correct! ite anions become ous acids. Don t get rid of the hypo prefix on the hypochlorite polyatomic ion. hypo is not the same as hydro (which isn t used for acids containing oxygen). This is an acid that contains oxygen. ClO -1 is hypochlorite ite polyatomic ions become ous acids. Hypochlorous acid The correct answer is (D).

8 No. 8 of Which of the following is Fe 2 O 3? (A) Iron oxide (B) Iron (II) oxide (C) Iron (III) oxide (D) Diiron trioxide (E) Iron trioxide Iron is a multivalent metal and needs Roman numerals to indicate the charge. Check your balancing of charges. C. Correct! The charge on iron is +3 in this compound. Don t use prefixes with ionic compounds. Don t use prefixes with ionic compounds. Iron is a multivalent metal and requires Roman numerals to indicate the charge. O -2 is oxide. There are three oxide ions, which gives a total negative charge of -6. Therefore there must be a total positive charge of +6. There are 2 iron ions to carry the +6 charge, so each is +3. Iron (III) oxide The correct answer is (C).

9 No. 9 of Which of the following is CO 2? (A) Carbon oxide (B) Monocarbon dioxide (C) Carbon dioxide (D) Carbonous (E) Carbon peroxide Use prefixes with covalent molecules. Don t use mono on the first element. C. Correct! We don t use mono on the first element. This is a covalent compound. Use prefixes for each element rather than trying to group them together. Peroxide is a polyatomic ion that only bonds with metal cations. Carbon is not a metal cation. Both of these atoms are non-metals and therefore this is a binary covalent compound. Use prefixes to indicate subscripts, but don t use mono on the first word. C is carbon O 2 is dioxide Carbon dioxide The correct answer is (C).

10 No. 10 of Which of the following is NH + 4? (A) Nitrogen tetrahydride ion (B) Ammonium ion (C) Ammonia ion (D) Nitrogen hydrogen ion (E) Nitrogen hydride ion This is a polyatomic anion. B. Correct! This is the ammonium cation. Ammonia is a molecule (NH 3 ), not an ion. This is a polyatomic ion. This is a polyatomic ion. This is the only polyatomic cation, called an ammonium ion. The correct answer is (B).