CHEMICAL REACTIONS AND EQUATIONS CLASS 10th

CLASS 10TH CHEMICAL REACTIONS AND EQUATIONS

1. CHEMICAL REACTIONS
AND EQUATIONS

2. CHEMICAL REACTIONS
•A chemical reaction is
a process that leads
to
the transformation of one set of chemical
substances to
another.
• Classically,
chemical reactions encompass
changes
that only involve the positions
of electrons in
the forming and breaking
of chemical
bonds between atoms, with no
change
to the nuclei, and can often be
described
by a chemical equation.

3. CHEMICAL REACTIONS ARE
EVERY WHERE
RESPIRATION

COOKING

4. CHEMICAL REACTIONS ARE
EVERY WHERE
FORMATION
OF CURD


RUSTING

5. Indications
of a Chemical
Reaction
•CHANGE
IN COLOUR
•EVOLUTION
OF GAS

6. •FORMATION
OF
PRECIPITATION
•CHANGE
IN
TEMPERATURE

7. CHEMICAL EQUATION
•A chemical equation is
the symbolic
representation
of a chemical reaction in
the
form of symbols and formulae.
• ex:-



magnesium
+ oxygen = magnesium oxide
•The
substances that undergo chemical
change
in the reaction (magnesium and
oxygen)
are the reactants.
•The
new substances (magnesium oxide)
formed
during the reactions is the product.

8. WORD EQUATION
•A
word – equation shows change of reactants
to
products through an arrow placed between
them.
•The
reactants are written on the left - hand
side
(LHS) with a plus sign between them.
•Similarly
, products are written on the right hand
side
(RHS) with a plus sign between them.
•The
arrowhead points towards the products,
and
shows the direction of the reactions.

9. SKELETAL EQUATION
•Skeletal
equation are those equation which
shows
the reactant and product so formed
without
balancing them.
•Example
:-


Mg
+ O
2


MgO


H
+ O H
2O
•It
is also known as unbalanced equation.

10. BALANCED EQUATION
•The
chemical equation needs to be
balanced
so that it follows the law of
conservation
of mass.
•A
balanced chemical equation occurs
when
the number of the different atoms of
elements
in the reactants side is equal to
that
of the products side.

13. How
to balance a equation
•This
is a reaction between methane (CH4)
and
oxygen (O2), producing carbon dioxide
(CO2)
and water (H2O)
•The
reaction shown is a combustion reaction:
a
compound reacts with oxygen and produces
carbon
dioxide and water. The technique is to
balance
the carbon (C) atoms first, then the
hydrogen
(H) atoms, and then the oxygen (O)
atoms.

14. •In
this case, the carbon (C) atoms are already
balanced.
So now we look at the hydrogen (H)
atoms.
There are 4 hydrogen (H) atoms on the
reactants
side and 2 hydrogen (H) atoms on the
products
side. To balance them, we put a
coefficient
of 2 in front of H
2O.

15. •The
hydrogen (H) atoms are now balanced.
Due
to the coefficient 2 in front of H2O, there
are
a total of 4 oxygen (O) atoms on the
products
side. To balance the oxygen atoms on
both
sides, we put a coefficient of 2 in front of
O2.
The chemical equation is now balanced.

16. WRITING SYMBOLS OF
PHYSICAL STATES
•The
physical states of the reactants and products
are
mentioned along with their chemical
formulae.
•The
gaseous, liquid, aqueous, and solid states of
reactants
and products are represented by the
notations
(g), (l), (aq), and (s), respectively.
•Sometimes
the reaction conditions , such as
temperature,
pressure, catalyst etc are indicated
above
or below the arrow in the equation

17. EXAMPLES

18. CHEMICAL
REACTIONS
TY
PE
S O
F CH
E
M
ICA
L R
E
A
CTIO
N

19. TYPES OF CHEMICAL REACTION
•COMBINATION REACTION
•DECOMPOSTION REACTION
•DISPLACEMENT REACTION
•DOUBLE DISPLACEMENT REACTION
•OXIDATION AND REDUCTION/REOX
REACTION

20. COMBINATION REACTION
•In
combination reaction , two or more
substances
combine to form a new
substance

•For
example –
•

C(s)
+ O
2(g)
CO
2(g)
•

2H2(g)
+ O
2(g)
2H
2O(g)

21. DECOMPOSITION REACTION
• In
a decomposition reaction , a single
compound
breaks down to produce two or
more
similar substences.
•The
decomposition reactions take place
when
energy is supplied in the form of
heat
, electricity or light.

22. ELECTROLYSIS
•When
a substance is decomposed by
passing
electric current, the process is
called
electrolysis.
•2H2O(I)
2H
2(g)
+ O
2(g)

23. THERMAL DECOMPOSITION
•When
a substance decomposes on
heating
it is called thermal decomposition.
•CaCO3(S)
C
aO(S)
+ CO
2(g)

24. PHOTOCHEMICAL DECOMPOSITION
•When
a substance is decomposed in
presence
of sunlight, it is called a
photochemical
decomposition.
•AgBr
Ag +Br

25. REACTIVITY SERIES
OF METALS
•Reactivity
series of metals is a series in which
the
metals arranged in the decreasing order of
their
reactivity.

27. DISPLACEMENT REACTION
•In
a displacement reaction , a more reactive metal
displaces
or removes another element from a
compound.
•For
example
•Zn(s)
+ CuSO
4(aq)

ZnSO4(s)
+Cu


In
the above reaction Zn is more reactive Cu, so Zn
displaces
Cu from CuSO
4.
•2AgNO3(aq)
+ Zn(s) → 2Ag(s) + Zn(NO
3)2(aq)


In
the above reaction Zn is more reactive than Ag , so
Zn
displaces Ag from its solution.

28. DOUBLE DISPLACEMENT
REACTION
•The
reaction in which two different atoms or group
of
atoms are displaced by other atoms or groups of
atoms
are double displacement reaction.
•For
example
•BaCl2(aq)
+ Na2SO4(aq) BaSO4(s) +




2NaCl(aq)
•Double
displacement reaction can be categorized
into
precipitation reaction and neutralization reacion

29. PRECIPITATION REACTION
•Precipitation
reactions occur when cations
and
anions in aqueous solution combine to
form
an insoluble ionic solid called a
precipitate.
• AgNO3
+ NaCl AgCl + NaNO
3

30. NEUTRALIZATION REACTION
•A
neutralization is a type of double replacement
reaction.
•In
the reaction, H
+

and OH
-

combine to form
HOH
or H
2O
or water molecules.
•A
salt is the product of an acid-base reaction.
•For
example
•HCl
+ NaOH NaCl +H
2O


In
the above reaction NaCl is the salt

31. A QUICK RECAP

32. EXOTHERMIC REACTIONS
•An
exothermic reaction is a chemical reaction that
releases
energy by light or heat. It is the opposite of an
endothermic
reaction.
•Expressed
in a chemical equation: reactants → products
+
energy


For
example


1)4Fe(s) + 3O
2(g) → 2Fe
2O
3(s)
2)Making ice cubes
3) Mixing sodium sulfite and bleach

33. ENDOTHERMIC REACTIONS
•Endothermic
reaction requires or takes in energy
in
order for it to proceed.
• This
required energy can be provided in many
forms,
but it is typically in the form of heat.


For
example


1)

Photosynthesis
2)

Melting ice


3)

NH
4
Cl
(s)

+ H
2
O
(l)

→


NH
4Cl
(aq)
- heat

34. RESPIRATION IS A
EXOTRHERMIC REACTIONS
•In
the process of respiration , the complex
substances
are broken down into similar
substances
and then converted to glucose. In
the
whole process, energy (or heat) is released.
•We
know that a reaction in which heat is
released
along with the formation of products is
known
as a exothermic reaction
•Thus
, from the above two points we can
conclude
that respiration is a exothermic
reaction
.

35. OXIDATION AND REDUCTION
REACTION
•Oxidation
is


1)
Addition of oxygen


2)
Removal of hydrogen
•Any
chemical substances following any theese is said
to
be oxidised.
•Reduction
is


1)
Removal of oxygen


2)
Addition of hydogen
•Any
chemical substences following any of these rules
is
said to be reduced.

36. •Reaction
involving both oxidation and reduction
process
, occuring simutaneously are known as
redox
reaction or oxidation and reduction
recaction.
•Example
•

37. OXIDISING AND REDUCING
AGENT
•An
oxidising agent is substance which
oxidises
something else.
•A
reducing agent reduces something else.
In
the equation, the carbon monoxide is the
reducing
agent.
•Oxidising
agents give oxygen to another
substance
or remove hydrogen from it.
•Reducing
agents remove oxygen from
another
substance or give hydrogen to it.

38. THE EFFECTS OF OXIDATION
REACTIONS IN EVERYDAY LIFE
1 )Corrosion
•Corrosion
is a natural process, which converts a
refined
metal to a more stable form, such as its
oxide,
hydroxide, or sulfide.

39. •Corrosion
engineering is the field dedicated to
controlling
and stopping corrosion.
•Corrosion
causes damages to car bodies, bridges ,
iron
raling, ships and to all objects made of metal ,
specially
those of iron.
•Corrosion
of iron is called rusting and it’s a serious
problem
. Every year an enormous amount of
money
is spent to replace damaged iron.
•The
rusting of iron can be prevented by painting ,
oiling
, galvanizing, anodizing etc
•Galvanization
is a method of protecting steel and
iron
from rusting by coating them with a thin layer
of
zinc

40. 2) Rancidity
• The
most important cause of deteriortion in
fats
and fatty food is oxidation.
• Rancidification,
the product of which can be
described
as rancidity, is the process which
causes
a substance to become rancid, that is,
having
a rank, unpleasant smell or taste.
•

41. P
revention of rancidity
•Storage
in coloured glass containers prevent
oxidation
of fats by rays of light.
•Vacuum
packaging retards rancidity by
excluding
oxygen.
•Naturally
occurring antioxidants like vitamin C, b
carotene
and vitamin E protect against rancidity.
•The
nitrogen also serves as a cushion ta
minimize
breakage of the chips during transport.

42. SOME IMPORTANT EQUATIONS

44. What Are Antacids?
Antacids
are medications that help neutralize stomach acid
to
relieve
heartburn, acid reflux, indigestion, and
ulcers.
They work by
increasing the pH level in the
stomach,
reducing irritation in the digestive tract.
Common Types of Antacids
•Aluminum-based
(Aluminum hydroxide)
•Magnesium-based
(Magnesium hydroxide)
•Calcium-based
(Calcium carbonate)
•Sodium bicarbonate

45. Side Effects of Antacids
While
generally safe, excessive or long-term use can cause:
1.Digestive Issues
1.Constipation
(especially with aluminum-based
antacids).
2.Diarrhea
(common with magnesium-based antacids).
2.Electrolyte Imbalance
1.Hypercalcemia
(too much calcium, leading to kidney
problems).
2.Hypophosphatemia
(low phosphate levels, causing
weakness).

46. 3. Kidney Problems
•Long-term
use may lead to
kidney stones
(calcium-based).
•Renal failure risk
in people with kidney disease
(magnesium-based).
4. Rebound Acid Production
•When
stopped suddenly, the stomach may produce
excess
acid,
worsening symptoms.
5. Interaction with Other Medications
•May
interfere with
antibiotics, blood pressure drugs, and
iron supplements
by affecting their absorption.

47. Precautions & Best Practices

✔
Use
antacids only for
short-term relief.

Avoid excessive use, especially ✔
if you have kidney
issues.

Consult a doctor if symptoms ✔
persist beyond two
weeks.

Take antacids ✔
separately from other medications
to
prevent absorption issues
.

48. Q1.What is the primary function of antacids?
a)
Reduce stomach acid
b)
Increase stomach acid
c)
Improve digestion enzymes
d)
Absorb nutrients
Q2. Which of the following is NOT a common ingredient in antacids?
a)
Magnesium hydroxide
b)
Aluminum hydroxide
c)
Sodium bicarbonate
d)
Sulfuric acid
Q3. Which side effect is commonly associated with aluminum-based
antacids?
a)
Diarrhea
b)
Constipation
c)
Increased appetite
d)
Low blood pressure
QUIZQUIZ

49. Q4. Which side effect is commonly associated with magnesium-based
antacids?
a)
Diarrhea
b)
Headache
c)
Dizziness
d)
Nausea
Q5.

Which of the following should be avoided when taking antacids?
a)
Drinking milk excessively
b)
Taking with water
c)
Eating a balanced diet
d)
Exercising
Q6. What is the best time to take an antacid?
a)
On an empty stomach
b)
Right after a meal
c)
Only before bed
d)
Any time without concern

50. Q7. Why should antacids not be taken with certain medications?
a)
They can increase drug absorption
b)
They can neutralize stomach acid needed for absorption
c)
They can make the medication stronger
d)
They have no effect on medications
Q8.
What precaution should be taken when using antacids long-term?
Q9.
Why should people with high blood pressure avoid sodium-based antacids?
Q10.
What is a safer alternative for acid reflux instead of frequent antacid use?
Q11.
True or False
a)
Long-term use of antacids can lead to kidney problems.
b)
Antacids can interact with antibiotics, reducing their effectiveness.

51. QUIZ

QUIZ

Q1.What
type of reaction occurs when two or more substances combine to form
a
single product?
a)
Decomposition reaction
b)
Combination reaction
c)
Displacement reaction
d)
Redox reaction
.
Q2.The
reaction:
2H
2
O
2
→2H
2
O+O
2
​
is
an example of:
a)
Combination reaction
b)
Decomposition reaction
c)
Redox reaction
d)
Both (b) and (c)
Q3.
In which type of reaction does a more reactive element replace a less reactive
element
in a compound?
a)
Combination reaction
b)
Decomposition reaction
c)
Displacement reaction
d)
Neutralization reaction

52. Q4.When
magnesium reacts with hydrochloric acid, which gas is released?
a)
Oxygen
b)
Carbon dioxide
c)
Hydrogen
d)
Nitrogen
Q5.Which
of the following is an example of a
double displacement reaction?
Fill in the Blanks
6.A
reaction in which a compound breaks down into two or more simpler substances is
called
a __________ reaction.
7.Rusting
of iron is an example of a __________ reaction.
8.A
reaction in which heat is absorbed is called an __________ reaction.
9.The
reaction between an acid and a base to form salt and water is called
__________.

53. True or False
10.A
decomposition reaction is always endothermic. (True/False)
11.In
a combination reaction, energy is always absorbed. (True/False)
12.Photosynthesis
is an example of an endothermic reaction. (True/False)
13.In
a redox reaction, both oxidation and reduction occur simultaneously.
(True/False)
14.A
double displacement reaction always produces a precipitate. (True/False)
Short Answer Questions
15.What
is a precipitation reaction? Give an example.
16.Define
oxidation and reduction with an example.
17.Why
is respiration considered an exothermic reaction?
18.What
happens when calcium carbonate is heated? Write the balanced
chemical
equation.
19.Differentiate
between endothermic and exothermic reactions with
examples.