Chemical Reaction And Equation Flashcards
(147 cards)
1
Q
What is an exothermic reaction?
A
A reaction where heat is released
‘Exo’ means exit and ‘thermic’ refers to heat.
2
Q
In which type of reactions do exothermic reactions mainly occur?
A
Combination reactions
3
Q
Provide an example of an exothermic reaction involving quicklime and water.
A
CaO(s) + H₂O(l) → Ca(OH)₂ (aq) + Heat
4
Q
What additional forms can energy take in an exothermic reaction?
A
Light or sound
5
Q
Write the equation for respiration as an exothermic reaction.
A
C₆H₁₂O₆ + 6O₂(g) → 6CO₂(aq) + 6H₂O(l) + energy
6
Q
What is the general formula for a combination reaction?
A
A + B → AB
7
Q
Provide an example of a combination reaction involving coal.
A
C(s) + O₂(g) → CO₂(g)
8
Q
Provide an example of a combination reaction that forms water.
A
2H₂(g) + O₂(g) → 2H₂O(l)
9
Q
Fill in the blank: An exothermic reaction releases _______.
A
heat
10
Q
True or False: All exothermic reactions produce light or sound.
A
False
11
Q
What is produced in the reaction of methane and oxygen?
A
CO₂(g) + 2H₂O(g)
12
Q
What are physical changes?
A
No new substance is formed, state changes, and it is reversible.
13
Q
Give examples of physical changes.
A
Melting of ice, tearing paper.
14
Q
What are chemical changes?
A
New substance is formed with different properties, change in chemical properties, and it is irreversible.
15
Q
Give examples of chemical changes.
A
Burning of paper, rusting of iron, cooking food, milk → curd (but curd → milk = not possible).
16
Q
What are indicators of a chemical reaction?
A
- Change in temperature
- Formation of precipitate
- Evolution of gas
- Change in color.
17
Q
What are reactants and products in a chemical reaction?
A
Chemical substances present on LHS are called reactants, and those on RHS are called products.
18
Q
What is a chemical equation?
A
An example is Mg + O₂ → MgO (Magnesium + Oxygen → Magnesium oxide).
19
Q
What is a chemical change?
A
A process in which the original substance loses its nature and forms a new substance.
20
Q
What is not considered a chemical change?
A
If only the state changes, it is not a chemical change.
21
Q
What are some common chemical reactions?
A
Combustion, rusting, photosynthesis, fermentation, respiration, rotting, etc.
22
Q
What are the physical states used in chemical equations
A
(l) = liquid, (g) = gas, (s) = solid, (aq) = aqueous
23
Q
What does (aq) mean in a chemical equation?
A
It means the substance is dissolved in water (aqueous).
24
Q
What symbols are used to represent conditions in chemical reactions?
A
Heat given: Δ
Catalyst used or temperature increased: Written above/below the arrow
25
What is a skeletal chemical equation?
An unbalanced chemical equation that doesn't follow the law of conservation of mass.
26
Why must we balance a chemical equation?
To obey the law of conservation of mass (atoms can't be created or destroyed).
27
Balance the equation:
Mg + O₂ → MgO
2Mg + O₂ → 2MgO
28
What is the balanced form of this equation?
NaOH + H₂SO₄ → Na₂SO₄ + H₂O
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
29
Identify the type of reaction:CuO + H2-------->Cu+H2O
Redox Reaction (CuO is reduced, H2 is oxidized)
30
What is the balanced chemical equation for:
Al + CuCl₂ → AlCl₃ + Cu
2Al + 3CuCl₂ → 2AlCl₃ + 3Cu
31
What is the balanced equation for photosynthesis?
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
32
What is decomposition Reaction?
Single reactant forms two or more product.
33
Give an example of decomposition Reaction?
FeSO4------>Fe2O3+SO2+SO3
34
Is decomposition an exothermic reaction?
No it is an endothermic reaction.
35
What happens when calcium carbonate is heated ?
It forms Calcium oxide and carbon dioxide
36
What is the chemical equation of Slaked lime and quick lime ?
CaOH2 is slaked lime while CaO is quick lime.
37
What are the types of decomposition?
Photolytic decomposition, Electrolytic decomposition and thermal decomposition.
38
What is Electrolytic decomposition?
Reactants break down by electric current. Eg- Electrolysis of water 2H2O -------> 2H2O2
39
What is photolytic decomposition?
Reactants break down due to sunlight. Eg - AgCl---->Ag + Cl2
40
What is used for black and white photography?
2AgBr----> 2Ag + Br2
41
What is thermal decomposition?
Reactants break down due to heat .
Eg- FeSO4------>Fe2O3+SO2+SO3
42
What is an endothermic reaction?
Endothermic reactions are the reaction in which heat is used.
43
What is the difference between displacement and double displacement reaction?
In displacement reaction more reactive elements displace the less reactive element while in double displacement reaction there is exchange of ions.
Displacement reaction is a slow reaction while double displacement is a fast reaction.
Displacement reaction eg -
CuSO4+Fe-----> FeSO4 + Cu
Double displacement eg-
Na2SO4+BaCl2---------->NaCl+BaSO4
44
Are all precipitation reactions double displacement reactions.
All double displacement reactions precipitate reactions.
True or false
1)True
2)False
45
What is the difference between oxidation and reduction ?
Oxidation - gain of oxygen loss of hydrogen gain of electrons
Reduction - loss of oxygen gain of hydrogen loss of electrons.
46
What is redox? Give an example.
Redox is the term used for reaction in which both oxidation and reduction occur.
Eg- CuO+H2----> Cu+ H2O
47
What is oxidising and reducing agent ?
Substance getting reduced is an oxidising agent as it oxidises other elements while the substance getting oxidised is reducing agent as it reduces the other elements.
48
State the reactivity series
Pottasium sodium calcium magnesium aluminum zinc iron lead hydrogen copper mercury silver gold
49
What is the reactivity series?
The series of elements containing elements according to reactivity
50
What are the effects of oxidation?
Corrosion and rancidity .
51
What is corrosion ?
It is a process which deteroites the quality of a substance due to moisture and chemicals
52
What are the effects of oxidation
Iron is used for foundation and due to corrosion the foundation becomes weak
It leads to tons of wastage of metal every year
53
What are the types of corrosion?
Rusting - due to moisture iron becomes reddish brown
Green coating on copper - indicates corrosion of copper
Black coating on silver - indicates corrosion of silver
54
What is the chemical equation of rusting of iron
Fe+O2+xH2O------->Fe2O3.xH2O
55
What is the chemical equation of corrosion of copper
2Cu+CO2+H2O+CuCO3------>CuCO3.Cu(OH)2
56
What is the chemical equation of the black coating on silver
Ag+2H2S+O2------->Ag2S+H2O
57
What are the prevention measures for corrosion
Regular painting
Machines should be oiled or greased
Galvanized(zinc coating) iron pipes should be used for water supply
Iron can be coated with chromium
58
What is Rancidity?
Food containing oil and fats gets oxidised by atmospheric oxygen causing faul idour and bad taste
59
What are prevention measures for Rancidity
Storing food in the fridge
Storing food in an air tight container
Addition of anti oxidants in food
Chips bags are flushed in nitrogen to prevent oxidation
60
What is the colour of Fe?
Grey
61
What is the color of Iron sulphate Fe2SO4
Green 🍏
62
What is the color of ferrous oxide Fe2O3
Reddish brown 🟤
63
What is the colour of copper
Reddish brown
64
What is the color of copper sulphate CuSO4
Blue
65
What is the color of copper sulphate anhydrous
White 🐻❄️
66
What is the color of copper nitrate Cu(NO3)2
Bluish green
67
What is the color of copper sulphide CuS
Black
68
What is the color of copper oxide CuO
Black
69
What is the color of copper chloride CuCl2
Green
70
What is the color of silver Ag
greyish white
71
What is the color of silver bromide AgBr
Pale yellow 🟡
72
What is the color of lead Pb
Bluish grey
73
What is the color of lead iodide PbI
Yellow 🟡
74
What is the color of lead oxide PbO
Yellow
75
What is the color of Barium Sulphate BaSO4
White
76
What is the color of Barium Br2
Reddish brown
77
What is the color of chloride
Yellowish green 🟡 🍏
78
What is the color of nitrogen oxide NO2
Brownish fumes
79
Why is magnesium ribbon cleaned before burning?
To remove the protective layer of magnesium oxide and allow proper reaction with oxygen
80
What do you observe when magnesium ribbon burns?
It burns with a dazzling white flame and forms white ash.
81
Write the chemical equation for magnesium burni in oxygen
2Mg+O
2
→2MgO
82
Magnesium burnt in oxygen write the type of reactions
Combination and oxidation reaction.
83
What is observed when zinc granules are added to dilute sulphuric acid?
Effervescence is seen due to hydrogen gas release.
84
How do you test that the gas is hydrogen?
Bring a burning matchstick near the mouth of the test tube — it burns with a pop sound.
85
Write the chemical equation and type of reaction when zinc granules are added in hydrogen sulphate .
Zn+H
2
SO
4
→ZnSO
4
+H
2
↑
Displacement reaction
86
What is the observation when Lead Nitrate and Potassium Iodide solution are mixedd
A yellow precipitate of lead iodide forms instantly
87
Write the chemical reaction whenLead Nitrate and Potassium Iodide are mixed and also the type of reaction
Pb(NO
3
)
2
+2KI→PbI
2
↓+2KNO
3
Double displacement and precipitation reaction.
88
What happens when copper powder is heated?
It turns black due to formation of copper oxide.
89
Heating Copper Powder
What causes the color change?
Reaction of copper with oxygen
90
Heating Copper Powder
Write the equation.
2Cu+O
2
→2CuO
91
Heating Copper Powder
Type of reaction?
Combination and oxidation reaction.
92
Iron Nail in Copper Sulphate Solution
What change occurs when an iron nail is dipped in copper sulphate?
The nail gets coated with brown copper, and the solution turns pale green
93
Iron Nail in Copper Sulphate Solution
Write the reaction. Chemical equation
Fe+CuSO
4
→FeSO
4
+Cu
94
Iron Nail in Copper Sulphate Solution
Type of reaction?
Displacement reaction.
95
Iron Nail in Copper Sulphate Solution Why does this happen?
Iron is more reactive than copper, so it displaces it from the solution.
96
Heating Ferrous Sulphate Crystals
What is observed when green ferrous sulphate is heated?
It becomes brown and releases a smell of burning sulphur.
97
Heating Ferrous Sulphate Crystals
Write the chemical equation.
2FeSO
4
Δ
Fe
2
O
3
+SO
2
+SO
3
98
Heating Ferrous Sulphate Crystals
Name the gases evolved.
Sulphur dioxide and sulphur trioxide.
99
Heating Ferrous Sulphate Crystals
Type of reaction?
Thermal decomposition.
100
Heating Lead Nitrate
What is the observation when lead nitrate is heated?
White crystals melt, and a brown gas (NO₂) is evolved.
101
Heating Lead Nitrate
Write the reaction
2Pb(NO
3
)
2
Δ
2PbO+4NO
2
+O
2
102
Heating Lead Nitrate
Name the brown gas.
Nitrogen dioxide (NO₂)
103
Heating Lead Nitrate
Type of reaction?
Thermal decomposition.
104
Electrolysis of Water
What is observed during electrolysis of water?
Bubbles of hydrogen at cathode and oxygen at anode in a 2:1 ratio.
105
Electrolysis of Water
Why is acid added to water?
To increase conductivity
106
Electrolysis of Water
Write the chemical reaction
2H
2
O
electricity
2H
2
+O
2
107
Electrolysis of Water
Type of reaction?
Electrolytic decomposition.
108
**Elements compound symbols and electrons**
Hydrogen
H1
109
**Elements compound symbols and electrons **
Helium
He2
110
**Elements compound symbols and electrons**
Lithium
Li 3
111
**Elements compound symbols and electrons**
Boron
B 5
112
**Elements compound symbols and electrons**
Carbon
C6
113
**Elements compound symbols electrons**
Nitrogen
N7
114
**Elements compound symbols and electrons**
Beryllium
4Be
115
**Elements compound symbols and valency**
Oxygen
O8
116
**Elements compound symbols and valency**
Fluorine
F9
117
**Elements compound symbols and valency**
Neon
Ne10
118
**Elements compound symbols and valency**
Sodium
Na natrium 11
119
**Elements compound symbols and valency**
Magnesium
Mg 12
120
**Elements compound symbols and valency**
Alluminium
Al13
121
**Elements compound symbols and valency**
Silicon
Si14
122
**Elements compound symbols and valency**
Phosphorus
P15
123
**Elements compound symbols and valency**
Sulphur
S16
124
**Elements compound symbols and valency**
Chlorine
Cl 17
125
**Elements compound symbols and valency**
Argon
Ar18
126
**Elements compound symbols and valency**
Potassium
K 19
127
**Elements compound symbols and valency**
Calcium
Ca 20
128
**Elements compound symbols and valency **
Zinc
Zn 2
129
**Elements compound symbols and valency**
Copper
Cu 1 or 2
130
**Elements compound symbols and valency**
Carbonate
CO3, 2
131
**Elements compound symbols and valency**
Hydroxide
OH -1
132
**Elements compound symbols and valency**
Lead
Pb2
133
**Elements compound symbols and valency**
Quick lime
CaO
134
**Elements compound symbols and valency**
Calcium carbonate
CaCO3
135
**Elements compound symbols and valency**
Sulphuric acid
H2SO4
136
**Elements compound symbols and valency**
Lead chloride
PbCl2
137
**Elements compound symbols and valency**
Potassium bromide
KBr
138
**Elements compound symbols and valency**
Sulphate
SO 2-4
139
**Elements compound symbols and valency**
Nitrate
NO3-, 1
140
**Elements compound symbols and valency**
Iron
Fe 2 or 3
141
**Elements compound symbols and valency**
Nitrogen dioxide
NO2
142
**Elements compound symbols and valency**
Slaked lime
Ca(OH)2
143
**Elements compound symbols and valency**
Glucose
C6H12O6
144
**Elements compound symbols and valency**
Natural gas
CH4
145
**Elements compound symbols and valency**
Sulphur dioxide
SO2
146
**Elements compound symbols and valency**
Silver chloride
AgCl
147
**Elements compound symbols and valency**
Ammonia
NH3
