petrol takes its latent heat of veporization from the finger
petrol takes its latent heat of fusion from the finger
water is more viscious than petrol
water has higher surface tension dan petrol
Explanation
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Discussions (16)
That's true the correct answer is A this is why.
[NB: what it is simply saying here is that when a drop of petrol is poured on your finger,you'l tend to experience a cooling sensation than that of when a drop of water is poured. This is due to the fact that
RAPID EVAPORATION CAUSES COOLING.
hence when water is being evaporated (cooling occurs) because water molecules escape with the heat energy .
but when rapid evaporation occurs in liquids like menthyleathed spirit [ether] and petrol , the escape with all heat energy of both it's own and the environment.
[Absorb all heat energy from their environment known as lantent heat of vapourization]
To prove
pour ether [spirit] in a beaker placed on a wooden piece, underath the beaker pour a little drop of water on the wooden piece, place beaker upon it.with the help of a straw or a tube blow air into it so that it begins to bubble,NB: evaporation takes place
and your observation would be that (rapid evaporation) causes the water poured on the wooden piece to freeze to ice and the beaker containing the ether slides off the wooden piece .
this is due to the fact that the ether absorbed the heat energy( lantent heat of vapourization of the water).
now for this question when you add a drop of petrol on your finger, you'l feel a cooling sensation because when air touches the petrol being poured on the finger rapid evaporation occurs causing the petrol to absorb its heat energy and that of the environment (the finger) as lantent heat of vapourization and then it evaporates.
NB: this principle does not apply to water.
But that explanation does not explain why it feels colder evaporating than water. Water also takes its heat from the finger. The correct answer is D. Firstly it compares both and it's true. Be careful before answering
The answer is wrong. Petrol taking it's heat from the finger does not explain why it feels colder. The right option is D
