A car is parked outside in the sun. The temperature of the interior of the car reaches 55 Celsius. However a company claims their product, a special spray, can cool down the temperature inside the car down to 25 Celsius in just a few seconds. The spray is a mixture of ten percent alcohol and 90 percent water.

Worth 3 marks!

please help.

I was thinking it has to do with the specific heat capacity of water and thermodynamics :/

oh and btw, this unit is on enthalpy.

Question

A car is parked outside in the sun. The temperature of the interior of the car reaches 55 Celsius. However a company claims their product, a special spray, can cool down the temperature inside the car down to 25 Celsius in just a few seconds. The spray is a mixture of ten percent alcohol and 90 percent water. 

Worth 3 marks!

please help.

I was thinking it has to do with the specific heat capacity of water and thermodynamics :/

oh and btw, this unit is on enthalpy.

wolfe8 · Answer

What does he question want lol. And is this a test? Btw nice name to go with this post.

anonymous · Answer

lol, thanks?

Right, i forgot to include the question :p The question is: "How does the spray work?"

Its not a test, just some question from an assignment that i am doing.

anonymous · Answer

@wolfe8

wolfe8 · Answer

Alright well, you are right about the specific heat. Tell me about the specific heat of water.

anonymous · Answer

water has a high heat capacity about 4.19 j/g.c and so it can absorb more heat from its surroundings

anonymous · Answer

how does it relate to enthalpy though?

wolfe8 · Answer

Correct. Hmmmm. I'm not sure how you can talk about enthalpy. I suppose you can say water can cause a huge enthalpy change of the surrounding? Not sure. 

Since it's 3 points worth, do you need 3 points in your answer?

anonymous · Answer

yeah, 3 points

the points has to relate to enthalpy or thermodynamics somehow

wolfe8 · Answer

Hoboy. Well for thermodynamics you can say that heat will move from the warmer air in the car to the cooler spray.

anonymous · Answer

ok, and does the alcohol play a role?

wolfe8 · Answer

I think alcohol is just to evaporate the solution. Otherwise your car will get wet.

anonymous · Answer

then once the water absorbs the heat, where does the heat go to?

wolfe8 · Answer

The heat is used to break the bonds of the molecules in the solution I believe. That is also why it evaporates.

anonymous · Answer

So does the hydrogen bonding between the alcohol and water molecules also make the substance absorb more heat in order for their bonds to break and evaporate?

wolfe8 · Answer

-squints eyes- Not sure. Let's look it up.

anonymous · Answer

i searched and i think evaporation has something to do with the cooling process

wolfe8 · Answer

Well I think it's what I said. The energy is used to turn liquid into gas basically.

anonymous · Answer

Well, okay. Thank you for your help :)

wolfe8 · Answer

You're welcome. Not sure I helped much but good luck.