Chemical equations (ch. 4 APC)

Question 0

Synthesis reaction

Answer 0

A + X –> AX

Ex) Al + S –> AlS
(3+) (2+) –> Al2S3

Question 1

Types of reactions

Answer 1

1. Synthesis (combination)
2. Decomposition
3. Single Replacement
4. Double replacement
5. Combustion

Question 2

Decomposition

Answer 2

AX –> A + X

ex) HBr –> H2 + Br2 (dr. H BrINClOF)
ex2) CCl4 –> C + 2Cl2

Question 3

Decomposition special cases

Answer 3

Endings in -ClO3 (hack off the O)
                  -(OH)2 (O and H2O)
                  -CO3 (get rid of co3) 
Ex1) LiClO3 --> LiCl + O2
Ex2) Mg(OH)2 --> MgO + H2O
Ex3) MgCO3 --> CO2 + MgO

Question 4

Synthesis special cases

Answer 4

Metal oxide + water
(Keep metal, add OH)
Ex) CaO + H2O –> Ca(OH)2

Question 5

Single Replacement Reaction

Answer 5

A + BC –> AC + B
-nonmetals replace nonmetals, metals replace metals

Ex) Zn + HCl –> H + ZnCl

Question 6

Double replacement reaction

Answer 6

AB + CD –> CB + AD
Always be 2compounds & 2compounds

Ex) AgNO3 + NaCl –> Na(NO3) + AgCl

Question 7

Combustion

Answer 7

Element or compound combining with O2, ALWAYS gonna end up
H2O + CO2

Ex)

Question 8

A chemically reaction prob occurred if…

Answer 8

• notable absorption or release of heat
• color change
• evolution of gas (bubbles may be visible)
• formation of a solid (precipitate) from two solutions

Question 9

Law of conservation of mass

Answer 9

The mass before and after a chemical equation remains constant

Question 10

Metathesis reactions

Answer 10

Reactions that do not involve electron transfer

All DR and N

Question 11

Redox reactions

Answer 11

Reactions that involve electron tranfer

Synthesis and decomp

Question 12

Oxidation number rules

Answer 12

• atoms in elemental form = 0
• monatomic ions = ion charge
• oxygen always = -2 (except peroxide and OF)
• hydrogen always +1
• oxidation states in compounds must sum to zero
• always assign the more electroneg element the negative ox number
• the oxidation state in a polyatomic ion must sum to the ion charge

Question 13

Oxidation

Answer 13

Loss of electrons

Question 14

Reduction

Answer 14

Gaining of electrons