moles/stoichiometry.....aim 1

what is a compound?

.....aims

home

aim 2.....

 

MU #1 A compound is a substance composed of two or more different elements that are chemically combined in a fixed proportion.

Example

H2O , Na2S, and H2SO4

 

MU #2 A chemical compound can be broken down by chemical means.

Example

H2O can be broken down chemically by electrolysis (the use of electricity) to produce H2 and O2

2 H2O(l)  à 2 H2(g) + O2(g)  

NaCl can be broken down chemically by electrolysis (the use of electricity) to produce Na and Cl2

2 NaCl(l) --> 2 Na(s) + Cl2(g)

 

MU #3 A chemical compound can be represented by a specific chemical formula and assigned a name based on the IUPAC system. 

IUPAC = International Union of Pure and Apply Chemistry

Example

Binary ionic compounds

When a metal and a nonmetal form a binary ionic compound, the metallic element is usually written first and the name of the nonmetal ends in -ide.

Note: Check the periodic table for the oxidation states of elements.

Problems

 

Name

Ions

Formula

potassium chloride

K+ and Cl-

KCl

calcium chloride

Ca2+ and Cl-

CaCl2

 

Na+ and S2-

Na2S

 

BaS

magnesium oxide

Al3+ and S2-

Li3N

beryllium oxide

 

 

 

 

 

 

 

 

 

 

 

 

Ionic compounds other than binary

Ionic compounds with more than two elements are usually combinations of a metal and a polyatomic ion or two polyatomic ion. See table E

Example

Sodium carbonate as the name suggests is composed of sodium and carbonate.

Sodium is Na+ and carbonate is a polyatomic ion CO32- (an ion composed of more than 2 atoms).

To keep neutrality 2 metallic ions Na+ are bonded to one CO32- carbonate.

Sodium carbonate = Na2CO3

Example

Magnesium nitrate as the name suggests is composed of magnesium and nitrate.

Magnesium is Mg2+ and nitrate NO3-  

To keep neutrality 2 nitrates are needed for every Mg2+  

Magnesium nitrate = Mg(NO3)2

Note: When more than one polyatomic ion are needed parenthesis are used

 

Problems

Name

Ions

Formula

NaNO3

Al3+ and NO3-

ammonium phosphate

Al2(SO3)3

zinc nitrate

 

Covalent compounds

When two nonmetals form a covalent compound, the name of the less electronegative element is usually written first and the name of the compound ends in -ide.

Example/problems

Prefix

Number

Formula

Name

mono-

1

CO

Carbon monoxide

di-      

2

CO2

Carbon dioxide

tri-     

3

SO3

Sulfur trioxide

tetra-  

4

N2O4

 

penta-  

5

P2O5

 

hexa-  

6

SCl6

 

hepta-

7

IF7

 

octa-

8

U3O8

 

nona-

9

 

 

deca-    

10

P4O10

 

 

The stock system

When a metal atom has more then one positive oxidation number the stock system is used. In the stock system, a roman numeral follows the positive ion to indicate its oxidation number. The stock system is used for ionic and also covalent compounds.

Example

Iron (II) nitrate is made of iron and nitrate but the iron has more than one oxidation number therefore; the Roman numeral II indicates the oxidation state of iron or +2

Iron (II) nitrate = Fe(NO3)2

 

Problems

 Name

Ions

Formula

 

Fe3+ and NO3-

Fe(NO3)3

copper (I) chlorite

 

 

copper (II) chlorite

 

Cu(ClO2)2

N+ and O2-

N2O5

nitrogen (III) oxide

NO

N4+ and O2-

lead (IV) chromate

 

Problems

Write the chemical formula corresponding to the name of the compound

 

magnesium oxide

lithium bromide

calcium nitride

aluminum sulfide

potassium iodide

strontium chloride

sodium sulfide

radium bromide

magnesium sulfide

aluminum nitride

cesium sulfide

potassium chloride

strontium phosphide

barium iodide

sodium fluoride

calcium bromide

beryllium oxide

strontium sulfide

boron fluoride

aluminum phosphide

rubidium oxide

calcium iodide

cesium oxide

magnesium iodide

lithium chloride

beryllium bromide

sodium oxide

calcium fluoride

boron phosphide

aluminum oxide

magnesium nitride

iron (III) oxide

sodium sulfate

copper (II) chloride

barium nitrate

aluminum hydroxide

mercury (II) phosphate

iron (II) chloride

copper (I) sulfide

lead (IV) iodide

tin (II) fluoride

mercury (I) bromide

tin (II) oxide

chromium (III) oxide

gold (I) iodide

manganese(II) nitride

cobalt (III) phosphide

iron (III) chloride

copper (II) sulfide

lead (II) bromide

tin (IV) iodide

mercury (II) fluoride

tin (IV) oxide

manganese(III) chloride

chromium (II) nitride

gold (III) oxide

cobalt (II) phosphide

tin (II) sulfide

mercury (I) sulfide

gold (III) bromide

manganese (II) oxide

chromium (II) chloride

lead (IV) nitride

cobalt (III) oxide

copper (II) iodide

tin (IV) fluoride

iron (II) phosphide

chlorine monoxide

oxygen difluoride

boron phosphide

dinitrogen monoxide

nitrogen trifluoride

sulfur tetrachloride

xenon trioxide

carbon dioxide

diphosphorous pentoxide

phosphorous trichloride

sulfur dioxide

bromine pentafluoride

disulfur dichloride

boron trifluoride

tetraarsenic decoxide

silicon tetrachloride

krypton difluoride

chlorine monoxide

silicon dioxide

boron trichloride

dinitrogen pentasulfide

carbon monoxide

sulfur trioxide

dinitrogen trioxide

dinitrogen monoxide

xenon hexafluoride

sulfur hexafluoride

phosphorous pentachloride

nitrogen monoxide

bismuth trichloride

silver carbonate

potassium hydrogen phosphate

aluminum hydroxide

sodium hydrogen carbonate

calcium acetate

potassium permanganate

calcium perchlorate

lithium carbonate

magnesium hydrogen sulfate

sodium hypochlorite

tin (IV) chlorite

mercury (II) phosphate

tin (II) carbonate

lead (II) chromate

copper (I) sulfite

iron (III) nitrate

potassium perchlorate

lead (IV) hydrogen carbonate

aluminum sulfate

iron (II) bicarbonate

barium hydroxide

tin (II) hydrogen sulfide

magnesium hydrogen sulfate

silver phosphate

cobalt (III) nitrite

ammonium sulfate

ammonium nitrate

   

Write the name corresponding to the chemical formula

MgS

KBr

Ba3N2

Al2O3

NaI

SrF2

Li2S

RaCl2

CaO

AlP

K2S

LiBr

Sr3P2

BaCl2

NaBr

MgF2

Na2O

SrS

BN

AlN

Cs2O

RbI

MgO

CaBr2

LiI

BeBr2

K2O

SrI2

BF3

Al2S3

CuS

PbBr4

Pb3N2

Fe2O3

FeI2

Sn3P4

Cu2S

SnCl2

HgO

Hg2F2

CuCl2

CuBr

PbO

Fe2S3

PbCl2

SnO

Cu2O

PbO2

FeO

SnO2

Hg2O

Hg2I2

AuCl3

MnO

CrCl3

CoO

Mn2O3

Co2S3

AuF

CrBr2

CrS

Cu2S

SnCl2

HgO

Sn3P4

Cr2S3

PbCl2

Sn3N4

FeS

FeBr3

HgF2

CuS

SnI4

Hg2O

Pb3P4

MnO

SnO2

PbO2

Fe2O3

CuI

Hg2Cl2

CuO

Sn3N2

Hg2O2

CuCl2

As4O10

BrO3

BN

N2O3

NI3

SF6

XeF4

PCl3

CO

PCl5