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| Exothermic reaction |
To measure the change in chemical reactions and
conclude whether the reaction is exothermic or endothermic.
AIM : To measure
the change in chemical reactions and conclude whether the reaction is
exothermic or endothermic.
THEORY : During the chemical reaction if the
temperature increases the reaction is exothermic and if temperature decreases
the reaction is endothermic.
APPARATUS :
Conical flask, 250 ml Beaker, Stand, Thermometer, Glass rod, measuring cylinder, stirrer.
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| Exothermic Reaction (step 1) |
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| Exothermic Reaction (step 2) |
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| Exothermic Reaction (step 3) |
MATERIAL
: Dilute hydrochloric acid, Zinc
metal, Solid ammonium chloride,
Observation
(1) initial temperature of dilute hydrochloric acid 0 C.
(2) Temperature of the mixture when Zinc metal dissolves in hydrochloric acid = 0 C.
(3) Difference of temperature = 0 C.
(4) Give chemical reaction of Zinc metal with hydrochloric acid.
NOTE :
(1) Similarly heat of
neutralization in neutralization reaction between dilute
hydrochloric acid and sodium hydroxide can be measured.
(2)
The increase in temperature can be noted when dissolution of solid sodium hydroxide in water is carried
out.
PRACTICAL USES
The combustion reactions of kerosene, Petrol, LPG are
exothermic, therefore these substance are used as fuel.
Endothermic Reaction :
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| Endothermic reaction (step 1) |
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| Endothermic reaction (step 2) |
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| Endothermic reaction (step 3) |
Observation
(1) Initial temperature of water =
0 C.
(2) Temperature o ammonium chloride solution when dissolved in water = 0 C.
(3) Difference between temperatures = 0 C.
NOTE : * Similarly when Sodium nitrite is dissolved
in water decrease in temperature occurs.
PRACTICAL USES
Some substances absorb heat from atmosphere, during the
reaction therefore used to reduce the temperature.
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