chemistry 161 chapter 2 compounds and chemical reactions
TRANSCRIPT
CHEMISTRY 161
Chapter 2
Compounds and Chemical Reactions
1. Structure of an Atom
subatomic particles
electrons(‘cloud’)
protons(nucleus)
neutrons(nucleus)
m(n) / m(e) ≈ 2000 m(n) > m(p)
2. Atomic & Mass Number
AZ Xatomic number
(number of protons)
(number of electrons)
mass number
(number of protons plus neutrons)
Compounds & Chemical Reactions
1. Compounds
2. The Chemical Formula
3. The Chemical Equation
4. Energy in Chemical Reactions
5. The Name of Chemicals
1. Compounds
molecular compounds ionic compoundsEXP1
Molecular Compounds
1. consist of electrically neutral particles called molecules
2. each molecule consists of atoms
3. atoms are connected via electrons
4. connections are called bonds(‘springs’)
EXP2
Molecular Compounds
Group Period IVA VA VIA VIIA Noble Gas 2 CH4 NH3 H2O HF Ne 3 SiH4 PH3 H2S HCl Ar 4 GeH4 AsH3 H2Se HBr Kr 5 SbH3 H2Te HI Xe
lots of molecules contain hydrogen
EXP3
H2, He
Jupiter
PH3
CH4
EXP4
H2, He
Saturn
NH3/PH3
CH4
H2O (s)
atom
(neutral)
add electron(s)
(reduction)
anion(Cl-)(negative charge)
take electron(s)
(oxidation)
cation(Na+)(positive charge)
Ionic Compounds I
1. consist of charged particles
2. charged particles are called ions
3. ions are formed by electron transfers from atoms
Ionic Compounds II
4. ionic compounds are held together by electrostatic forces
Cl-Na+metal non-metal
NaCl MgO EXP5
2. The Chemical Formula
collection of chemical symbols used to describe the composition of
elements and compounds
HeEXP6
F F
F2
O2
O O
S8
N2
N N
P4
H2
H H
2. The Chemical Formula
collection of chemical symbols used to describe the composition of
elements and compounds
NaCl
H2O Fe2O3
CaSO4 2 H2O
Compounds & Chemical Reactions
1. Compounds
2. The Chemical Formula
3. The Chemical Equation
4. Energy in Chemical Reactions
5. The Name of Chemicals
3. The Chemical Equation
chemical equation describes what happens in a chemical reaction
chemical reaction is combination of elements and/or compounds
H2 + O2 H2O
balancing & mass conservation
2 2
3. The Chemical Equation
2 H2 + O2 2 H2O
s = solid l = liquid g = gas aq = aqueous solution
2 H2(g) + O2 (g) 2 H2O (l)
1.phosphor with oxygen
2. sulfur with oxygen
Examples
3. methane with oxygen EXP7
Compounds & Chemical Reactions
1. Compounds
2. The Chemical Formula
3. The Chemical Equation
4. Energy in Chemical Reactions
5. The Name of Chemicals
4. Energy in Chemical Reactions
a chemical reaction either absorbs or releases
energy(heat or light)
releasing energy (heat) exothermic
absorb energy (heat) endothermic
EXP1/2
CONSERVATION OF ENERGY
KINETIC ENERGY
POTENTIAL ENERGY
energy of an object due to its motion
Ekin = ½ m v2
energy of an object due to its position
Epot = m g h
Etotal = Epot + Ekin = constant
chemical energy is a form of potential energy
EXP3
Compounds & Chemical Reactions
1. Compounds
2. The Chemical Formula
3. The Chemical Equation
4. Energy in Chemical Reactions
5. The Name of Chemicals
Organic Compounds
compounds containing mostly hydrogen and carbon
minor amount other elements (N, O, S, P…)
hydrocarbons
H C
alkanes CnH2n+2
CO2
CO H2O
H2COC4H10
Organic Compounds?
C4H10 combustion
EXP4
Titan – Saturn’s Largest Moon
Cassini-Huygens Mission
Cassini-Huygens Mission
Inorganic Compounds
binary compounds
compounds consisting of ONLY TWO different elements
NaCl CO2 CaSO4
nomenclature naming compounds
nomen (Latin) = name
symbol stem first element second element O ox- oxygen oxide S sulf- sulfur sulfide N nitr- nitrogen nitride P phosph- phosphorus phosphide F fluor- fluorine fluoride Cl chlor- chlorine chloride Br brom- bromine bromide I iod- iodine iodide
part one (metal)
part two
English name ofelement
stem + ide
NaCl MgO BeS
Metal (Main Group) + Non-Metal
ionic compounds
(metal + non-metal)
stem + ide
Nomenclature Inorganic Compounds
main group
metal metal +
Greek Prefixes mono- = 1 (often omitted) hexa- = 6 di- = 2 hepta- = 7 tri- = 3 octa- = 8 tetra- = 4 nona- = 9 penta- = 5 deca- = 10
PF3 PF5
CO CO2
HCl
NO NO2N2O5
Molecular Compounds
ionic compounds
(metal + non-metal)
stem + ide
Nomenclature Inorganic Compounds
main group
metal element +
molecular compounds prefix + element + prefix + stem + ide
ionic compounds
(metal + non-metal)
stem + ide
Nomenclature Inorganic Compounds
main group
metal
trans. group
metal
element +
molecular compounds prefix + element + prefix + stem + ide
ionic compounds
cations & anions
Mn+ Em-
metalstransition metals
nonmetals
compounds must be electrically neutral
charge state of ions
-/+3/5 -2 -1 0+1 +2 +3
-/+2/4
K2S CaCl2
main group metals – always start with cation
Chromium Cr2+, Cr3+ Zinc Zn2+ Manganese Mn2+, Mn3+ Silver Ag+ Iron Fe2+, Fe3+ Cadmium Cd2+
Cobalt Co2+, Co3+ Gold Au+, Au3+ Nickel Ni2+ Mercury Hg2
2+, Hg2+ Copper Cu+, Cu2+
NiCl2 CuO CuCl
transition metals – always start with anions
include oxidation state in name – no prefixes
Mn2O3 B2O3
ionic compounds
(metal + non-metal)
stem + ide
Nomenclature Inorganic Compounds
main group
metal
trans. group
metal
element +
molecular compounds prefix + element + prefix + stem + ide
stem + idemetal + oxstate +
molecular compounds
ionic compounds
polyatomic ionic compounds
ion name ion name NH4
+ ammonium ion CO32- carbonate ion
OH- hydroxide ion H3O+ hydronium ion
NO2- nitrite ion SO3
2- sulfite ion NO3
- nitrate ion SO42- sulfate ion
ClO2- chlorite ion CrO4
2- chromate ion ClO3
- chlorate ion Cr2O72- dichromate ion
PO43- phosphate ion
ammonium chloride sodium dichromate magnesium carbonate
rubidium sulfate calcium phosphate
molecular & ionic compoundsproperties
melting point
molecular compounds – weak interactions (gases, liquids) – low melting point
ionic compounds – strong interactions (solids) – high melting point
electrical conductivity
molecular – do not conduct electricity in solid or liquid state
ionic – do not conduct electricity in solid state
ionic – conduct electricity in liquid and aqueous state
Compounds & Chemical Reactions
1. Compounds
2. The Chemical Formula
3. The Chemical Equation
4. Energy in Chemical Reactions
5. The Name of Chemicals