00:01
First of all, we have given combustion.
00:03
So, combustion reaction.
00:06
This is a reaction in which the hydrocarbons get burnt in the presence of oxygen.
00:13
Oxygen is the supporter of combustion.
00:16
And this leads to formation of carbon dioxide, water, and light and heat energy.
00:24
Okay.
00:25
So since heat energy is released, so you can see that.
00:30
Combersion is an exothermic reaction, okay? that is, it releases heat.
00:38
So, combustion releases heat, hence is exothermic.
01:10
Okay? now, b part, we have, so we all know condensation.
01:20
What is condensation? condensation is the process by which water vapor or we have any gas form that converts to liquid form okay so in case of water vapor that changes to liquid water so now in this case we know that molecules in gas so they move randomly and very very quickly but in the case of liquid when they change to liquid so they have to move slow than that in gas.
01:58
So when these water moves from gas phase to liquid phase, they must release some kind of energy.
02:07
And since the energy is released, that is in the form of heat.
02:11
And that's why we can say that condensation is a type of exothermic reaction.
02:17
So for condensation, the molecules, that is we are talking about water molecules here okay so the molecules are giving up their energy hence is exothermic then we have c part so we have a reaction here in which we have co2 in solid state and this converts in co2 in gaseous state okay so you can can see that the solid phase changes to gas yes phase.
03:33
So such a phenomenon is called sublimation.
03:36
We all know right...
