Chp 6- Chemical Reactions Flashcards
08/4/202* CHEMICAL REACTIONS
- SYNTHESIS REACTION
+ B AB
Definition • Reaction in which two or more elements or
compounds combine to give one new compound.
4 K + 02 > 2K20
2 Zn + → 22n0 [Yellow-hot
white -cold ]
4 Fe + 302 mosturg 2 Fe 2 03 [Rust ]
3 Fe + 20г → Fez 04 [Black
solid powder ]
2 Cu + 02 -
2 c ú a [Black ]
+ -
2HgO [ Orangish-red ]
2 Hg
- Metal + Oxygen → Metallic Oxide
- Non-metal + Oxygen → Non-metallic oxide
2H2
9
4P
electric
s p a r k
+
02 2H20
+
→ 50
LToxic gas ]
+ 502 → 2P205 [shite
crystalline solid ]
- Element + Chlorine - Chloride
+ A2 → 2 HCL
[occurs in presence of diffused sunlight
• not a photochemical
reaction ]
2 Fe
Cu
+ 3Ul2
+ U2
- 2 Fellz
[Brown scales]
- Element + Sulphur → Sulphide
2n + S
Fe + S
A g + S
4 7 2 n 5
A
Fes [Black]
→ Agzs (Black]
- Element + Nitrogen → Nitride
A
3 Ca + N2
3 Ма + N2
burning)
Ca
N2
→ Mg3 N2
2 AL + N2
- AL
AZALN
N2
5 0 Oatm
+ 3H2 F Fe / 450-500°c 2NH3 + A
- Lower oxide + Oxygen → Higher oxide
2 C0
+ 02
2502 +. 02
2 NO + 02
4 Fe 0 + 02
→ > 2002
230 г
DE 2N02
→ 2Fe203 [Rustl
- Soluble metal oxide + water → Alkali [water-soluble bases ]
Na
0
K20
Cao
+ H20
+A H20
+ H20
- >
-
ー >
Na OH [caustic soda I
кОН (caustic potash ]
Ca (OH)2 [slaked Lime ]
- Soluble non-metal oxide + water acid
C02
502
SO3
P205
+
+
+
H
0
H20
H20
+ 3H
0
- → >
H2C03 [caxbonic acid ]
- >
H290g [sulphurous acid ]
- H
S04 [sulphuric acid ]
→ 2H3P0u Lphospharic acid ]
DECOMPOSITION REACTION
AB -A + B
Definition: Reaction in which a chemical compound decomposes.
into two or more simpler substances
K
Na
Oxides of metals from a to C u Hg
are
stable to heat
K
0
A
K
Ca
Oxides of Hg and Ag
decompose to give the
metal and oxygen
HgO - Hg + 02
Ag
0 = → Ag + 02
AL
2n
Fe
Pb
Higher oxides → lower oxides
2 P602
А
6P60
02 +
02 دث + 0 6 P 2
[н]
Cu
Cuo → CuO
- Decomposition of carbonates
K
Na
Carbonates of K & Na are
STABLE TO HEAT
К
СОз
Na
CO3 Na
Carbonates from Ca t o Cu DECOMPOSE on heating to give the
METALLIC OXIDES & CARBON DIOXIDE
A_
CaO + CO2
AL
AL
(03) 3 AL
Zn CO з
ZnO + C02
み
Fe CO _A
Fe O
+ €02
Pb
[ н ]
Cuo + CO2
Carbonates o f Hg& Ag DECOMPOSE on heating t o give t h e
METAL
CARBON DIOXIDE
2Hg CO3 - 2Hg + 2002
2A92002 A
4A9 + 2002 4 02
- Decomposition of hydroxides
K
Na
Hydroxides of K & Na are STABLE TO HEAT
КОн
кОн
NaOH
NaOH
Ca
1 g
Hydroxides from ca to Cu DECOMPOSE on heating to give
METALLIC O X I D E & WATER
ca (OH) 2 •
CaO + H20
AL AL (OH) 3 Al
03 + 1
吃 Y
Zn ( ОН ) 2 → Zn0 + H20
Fe Fe (OH) 2 Fe 0 + 420
C H ］
c u Cu (OH)2
> CuO + H20
Hydroxides of Hy& Ag DECOMPOSE on heating to give the
METAL
OXYGEN 2 WATER
Hg (OH) 2 A Hg + 0
+ H
А д OH Ag + 02+ H20
- Decomposition of nitrates :
Na
Nitrates of K & Na SLOWLY DECOMPOSE ON HEATING to give
METALLIC NITRATE l a OXYGEN:
KNO3 - KNO
+ 02
Nitrates from Ca to cu decompose o n heating to give the
METALLIC OXIDE
NITROGEN DIOXIDE
My 2Mg (NO3) 2 - 2Mg0 +4N02 + 02
AL 4AL (NO3) 3 A DALO3 H2N0
2802
220 (NOz) 2 22n0 + 4N02 + 02
일
(н ]
매
Cu2 CU (NO3)
→ 2 CuO + 4N02 + 02
Nitratus o f Hg & Ay decompose on heating to giuc thc
METALIE
OXYGEN
AgNOz 4
Ag + 0
SIMPLE DISPLACEMENT REACTION:
Definition: Reaction in which one element displaces
another element from its conpound and takes its place
AB + → AC
+ B
Elements placed higher in the activity series of metals
can displace tre elements placed below it from a :
solution of its compound.
K
C a
Na Zn + Mgulz → not possible
Mg * Metals above Hydrogen in the activity series can s
AL displace it from water.
In (i) Potassium
Sodium and Calciuin can displace hydrogen
Fe from cold water
РЬ
[н]
Cu
2 K + 2K20
2 Na + 2H
0
Ca H
0
→ 2 KOH + H2
→ NaDH + H2
→ Ca OH)2+ H2/
AL
@ Les reactive metals like magnesium
zinc
can displace hydrogen from water to form the correspand
ing oxide and liberate hydrogen.
My + H20 → Mgo + H
AL uH20 → Alz03 + H2
+ H20
ZnO r H2
Fe H20 F
(steam) Fez 0y + H2
Note: Magnesium can also liberate hydragen from bailing
water.
(i) Lead and metals below hydrogen do not react with
water or steam to liberate hydrogen.
(i) Acids are compounds that contain Ht ions as their
only positive ion.
• K
Na
with an explosion.
2K + 2HU →
(cold
dilutc)
2 KCh +
• Mg
AL
dilute acids [Now violent reactions ]
Zu Cl2 + H2
7n + 2 HCL
(cold
dilate)
• Iron displaces hydrogen trans cold
dilute acids slowly
and quietly.
Fe + HCL → Fellz H2
• Lead displace hydrogen from hot
concentrated acid
acid.
Pb + 2Ha → PbCL2 +
H2
(hot
conc.) 4 0 1 9 d
• Metals below hydrogen do not displace it from acids
- DOUBLES DECOMPOSITION REACTION
AB + co ⼀ と - A D + CB
Delinition: Reaction in which both reactants/ compounds
are decomposed to give new compounds by exchanging
radicals.
• Neutralization Reactions :
These kind of reactions occur when acids and bases
exchange their radicals/ions to form salt and water.
Acid 1+ Base → Salt + Water
н а + NaOH → Naul + H20
H2S0u + 2K0H → K2S0
+ 2H20
2 HNO3 + Ca (QH)2 → Ca (NOs) 2 + H20
HCL + cuO
• Precipitation Reaction.
When 2 compounds in their agueous state react to
torm an insoluble residue as one ot the products.
the residue is called the precipitate and the
reaction is called pricipitation reaction.
Nall
AaNOz
(aq)
→ NaNOz+ Agal v
Pb NO3)
- Na
NaDH → > NaCl +
Fe (OH) 2k
(aq)
dirty green)
Fe Uz
(aq)
Na OH →
( 9 g )
N a u
+ AFe (OH) 3 V
(reddish brown)
1 0 2 40X8 + 2 0 2 H
(HO)
+
- OXIDATION REDUCTION
02 + - 0 H2 + H2
e s
2
H28 + → 2HCL + S
82 - 2é’s → 3°
(loss of electrons: oxidation) ร า ง ห า 0 ) A
A i r o m m e o t n e g o r t i n [ o
C2 - HCL
2CL° + 2 é s → 2kl
(gain of electrons: reduction)
H2S i s oxidised to s
H2S + CL2 → 2HU + s
a is reduced to a
Oxidising agent : A substance that bring about oxidation i.e.
oxidises another substance is called an oxidising agent.
Reducing agent: A substance that brings about reduction i.e.
reduces another substance is called a reducing agent.
