Chemical Compounds and Formulas

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Questions and Answers

What is the name of the acid derived from the anion sulfite (SO3)?

Sulfuric acid

Sulphuric acid

Sulfidic acid

Sulfurous acid (correct)

Which of the following acids contains one more oxygen atom than the common acid chloric acid?

Chloric acid

Chlorous acid

Hypochlorous acid

Perchloric acid (correct)

What is the correct name for HClO2?

Hypochloric acid

Chloric acid

Chlorous acid (correct)

Hydrochloric acid

How is the acid with no oxygen, HCl, named?

Hydrochloric acid Signup and view all the answers

What do you call acids that are derived from anions ending in –ite?

–ous acids Signup and view all the answers

What does the formula H2O represent?

A compound consisting of two hydrogen and one oxygen atom Signup and view all the answers

What is the charge of an atom that loses electrons?

Positive charge Signup and view all the answers

What is the name for Fe2(SO4)3 using the Stock System?

Iron (III) sulfate Signup and view all the answers

Which of the following correctly describes the naming of ionic compounds?

The cation name is derived from the metal, followed by the anion with an –ide ending Signup and view all the answers

What is a hydrate?

An ionic compound that absorbs water in its solid structure Signup and view all the answers

Which prefix indicates the presence of five water molecules in copper sulfate?

penta Signup and view all the answers

Which of the following pairs represents correct application of the crossover rule?

Na1Cl1 for sodium chloride Signup and view all the answers

How is the name of an oxyacid derived from an oxyanion ending in -ite formed?

It ends in -ous acid Signup and view all the answers

When naming ionic compounds with variable oxidation states, what suffix is used for lower oxidation states?

-ous Signup and view all the answers

What is the correct name for CO2 in the context of naming non-metal compounds?

Carbon dioxide Signup and view all the answers

What is a common property of anhydrous substances?

They are free from water Signup and view all the answers

Which of the following is the correct name for HCl according to chemical naming conventions?

Hydrogen chloride Signup and view all the answers

What is the oxidation state of iron in Iron (II) chloride?

II Signup and view all the answers

In the naming of ionic compounds, how is the name of the anion typically formed?

By changing the ending to –ide Signup and view all the answers

What is the suffix change when naming an oxyacid derived from a -ate anion?

-ic acid Signup and view all the answers

Which of the following compounds contains a tetravalent compound indicated by its prefix?

N2O4 Signup and view all the answers

Study Notes

Chemical Formulas

A chemical formula shows the elements present in a compound and their relative proportions.
The formula H2O represents water, which is composed of hydrogen and oxygen in a 2:1 ratio.

Oxidation Numbers

Oxidation numbers are positive or negative integers that reflect the charge of an atom in a compound.
They are used to keep track of the number of valence electrons lost or gained by an atom.
A positive oxidation number indicates an atom has lost electrons.
A negative oxidation number signifies an atom has gained electrons.
For polyatomic ions, the charge of the ion is distinct from the oxidation numbers of the constituent elements.

Naming Ionic Compounds

Writing Ionic Compound Formulas
- The metal (cation) is written before the non-metal (anion).
- The cross-over rule applies, using the absolute values of the charges (oxidation numbers) of the anion as the subscript for the cation and vice versa.
- Example: NaCl (Sodium chloride), Mg3(PO4)2 (Magnesium phosphate).
Naming Ionic Compounds
- The name follows the order of the ions in the formula.
- The metal (+ion) name comes first, followed by the non-metal (-ion) name.
- The cation retains the metal's name, while the anion's name is derived by changing the ending to -ide.
- Example: LiBr (Lithium bromide), Na2O (Sodium oxide), AlI3 (Aluminum iodide).
Naming Ionic Compounds with Variable Oxidation Numbers
- Metals with variable oxidation states can be named using two systems:
  - Old System: The Latin name of the cation is modified to end in -ous for the lower oxidation state and -ic for the higher oxidation state.
  - Stock System: The English name of the metal is used, with the oxidation state indicated by a Roman numeral enclosed in parentheses.
- Example: FeCl2 (Ferrous chloride or Iron (II) chloride), Fe2(SO4)3 (Ferric sulfate or Iron (III) sulfate).
Naming Hydrates
- Hydrates are ionic compounds that incorporate water molecules into their solid structures.
- Anhydrous substances are water-free.
- Greek prefixes are used to indicate the number of water molecules in the formula.
- Example: Copper (II) sulfate pentahydrate.
Naming Compounds with Polyatomic Ions
- Name the first polyatomic ion followed by the second polyatomic ion.
- Example: (NH4)3PO4 (Ammonium phosphate).

Naming Compounds of Non-metals

Binary Compounds
- The name of the first element (appearing first in the formula) is written first.
- The second part of the name is formed by adding the -ide suffix to the stem of the second non-metal.
- Example: HCl (Hydrogen chloride), H2S (Hydrogen sulfide).
Compounds with Multiple Non-metals
- Greek prefixes are used to indicate the number of atoms of each element present.
- Example: NO (Nitrogen oxide), CO (Carbon monoxide), NO2 (Nitrogen dioxide), CO2 (Carbon dioxide), N2O (Dinitrogen oxide), CO3 (Carbon trioxide), N2O4 (Dinitrogen tetroxide), SO2 (Sulfur dioxide), SO3 (Sulfur trioxide).

Oxyacids

Oxyacids are derived from oxyanions.
Naming Oxyacids
- If the oxyanion name ends in -ate, the oxyacid name will be -ic acid.
  - Example: SO42- (Sulfate), H2SO4 (Sulfuric acid)
- If the oxyanion name ends in -ite, the oxyacid name will be -ous acid.
  - Example: ClO2- (Chlorite), HClO2 (Chlorous acid)
Prefixes and Suffixes for Oxyacids
- per-ic denotes an acid with one more oxygen atom than the common acid.
  - Example: HClO4 (Perchloric acid).
- -ic denotes the common acid.
  - Example: HClO3 (Chloric acid).
- -ous denotes an acid with one less oxygen atom than the common acid.
  - Example: HClO2 (Chlorous acid).
- hypo--ous denotes an acid with two less oxygen atoms than the common acid.
  - Example: HClO (Hypochlorous acid).
- hydro--ic denotes an acid with no oxygen.
  - Example: HCl (Hydrochloric acid).

Bases

Compounds identified by the presence of hydroxide group (OH-)
To name bases, name the metallic portion first, followed by the word hydroxide.
Example: KOH (Potassium hydroxide), Fe(OH)2 (Ferrous hydroxide or Iron (II) hydroxide), Fe(OH)3 (Ferric hydroxide or Iron (III) hydroxide).

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Description

This quiz covers essential concepts related to chemical formulas, oxidation numbers, and the naming of ionic compounds. You'll explore how to read and write formulas, understand oxidation states, and apply the cross-over rule in ionic compounds. Ideal for students studying chemistry.