Naming Compounds
Day 2
Working backwards: name to formula
• It’s possible to determine a formula from a name
• E.g. What is the formula of sodium oxide?
• To get the answer, first write the valences:
Na1O2  Na2O
• What is the formula of copper(II) oxide?
Cu2O2  Cu2O2  CuO
• For covalent compounds, simply use the
prefixes to tell you the number of each element:
• What is the formula for dinitrogen trioxide?
N 2O 3
• Give formulae for: lithium sulfide, dinitrogen
monoxide, lead(IV) sulfate
Write and name the following
covalent compounds
lithium sulfide
Li1S2  Li2S
dinitrogen monoxide
N2O
lead(IV) sulfate
Pb4(SO4)2  Pb2(SO4)4  Pb(SO4)2
Assignment
1. Name each according to the rules:
a) ZnS, b) FeCl3, c) CaCO3, d) P2O5, e) NaCN,
f) N2F2, g) MgHPO4, h) Cu(BrO3)2, i) K2O, j) BF3
2. Give the valence of a) Fe in FeO, b) Mn in MnO2
3. Write formulas for: a) sodium oxide,
b) potassium iodide, c) plumbic sulfide,
d) mercury(I) oxide, e) ferrous oxide,
f) iron(II) phosphate, g) copper(II) fluoride,
h) dichlorine monoxide, i) silver sulfide,
j) magnesium nitride, k) aluminum hypochlorite,
l) iodine pentafluoride, m) calcium chromate,
n) diphosphorus pentasulfide
Complete exercises on handout
Steps:
1. Determine if its ionic or covalent
2. If ionic, determine if its metal has one
or more valence
3. Name according to appropriate rules
Answers – 1, 2
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
zinc sulfide
iron(III) chloride
calcium carbonate
diphosporus pentoxide
sodium cyanide
dinitrogen difluoride
magnesium hydrogen phosphate
copper(II) bromate
potassium oxide
boron trifluoride
2 a) 2
b) 4
Answers – 3
a) Na2O
h) Cl2O
b) KI
i)
Ag2S
c) PbS2
j)
Mg3N2
d) Hg2O
k) Al(ClO)3
e) FeO
l)
f)
m) CaCrO4
Fe3(PO4)2
g) CuF2
IF5
n) P2S5
Naming Acids: Binary acids
• All acids start with H (e.g. HCl, H2SO4)
• 2 acids types exist: binary acids and oxyacids
Binary: H + non-metal. E.g. HCl
Oxy: H + polyatomic ion. E.g. H2SO4
• Each have different naming rules.
Naming Acids: Binary acids
Binary acids: naming depends on state of acid
• If it’s not aqueous: hydrogen + non-metal
HCl(g) = hydrogen chloride
• If it is aqueous: hydro + non-metal + ic acid
HCl(aq) = hydrochloric acid (aqueous hydrogen
chloride)
HBr(s) hydrogen bromide HI(aq) hydr(o)iodic acid
H2S(aq)
H2S(g) hydrogen sulfide
hydrosulfuric acid
Naming Acids: Oxyacids
• Naming does not depend on the state (aq)
• 1) name the polyatomic ion
2) replace ate with ic, ite with ous
3) change non-metal root for pronunciation
4) add “acid” to the name
E.g. H2SO3
1) sulphite,
2) sulphous,
3) sulphurous, 4) sulphurous acid
HNO2
hypochlorous acid
H3PO4(aq)
carbonic acid
Naming Acids: Oxyacids
• Naming does not depend on the state (aq)
• 1) name the polyatomic ion
2) replace ate with ic, ite with ous
3) change non-metal root for pronunciation
4) add “acid” to the name
E.g. H2SO3
1) sulphite,
2) sulphous,
3) sulphurous, 4) sulphurous acid
HNO2
hypochlorous acid
- nitrous acid
- HClO
H3PO4(aq)
carbonic acid
- phosphoric acid
- H2CO3
Assignment: give formula or name
a) chloric acid
b) hydrosulfuric acid
c) hydrobromic acid
d) phosphorous acid
e) iodic acid
f) HCl(g)
g) HCl(aq)
h) H2SO4(s)
i) H2SO4(aq)
j) HClO2
k) HF(aq)
a) HClO3
b) H2S(aq)
c) HBr(aq)
d) H3PO3
e) HIO3
f) hydrogen chloride
g) hydrochloric acid
h) sulfuric acid
i) sulfuric acid
j) chlorous acid
k) hydrofluoric acid
Hydrates
• Some compounds contain H2O in their structure. These compounds are called hydrates.
• This is different from (aq) because the H2O is
part of the molecule (not just surrounding it).
• The H2O can usually be removed if heated.
• A dot separates water: e.g. CuSO4•5H2O is
copper(II) sulfate pentahydrate.
• A greek prefix indicates the # of H2O groups.
Na2SO4•10H2O sodium sulfate decahydrate
nickel(II) sulfate hexahydrate
NiSO4•6H2O
sodium carbonate monohydrate Na2CO3•H2O
BaCl2•2H2O
barium chloride dihydrate