Butane, C4H10, has a boiling point of -0.5 °C (which is 31 °F). Despite this, liquid butane can be seen sloshing about inside a typical butane lighter, even at room temperature. Why isn't the butane boiling inside the lighter at room temperature? Select all that apply.


1. Boiling occurs when the vapor pressure equals the surrounding pressure.

2. Vapor pressure increases with increasing of temperature.

3. Vapor pressure decreases with increasing of temperature.

4. The pressure inside the lighter is higher than normal atmospheric pressure.

5. None of these.


I think 3,4 are correct.
But, I am not sure about this one.
What do you think about this problem?

Thank you

The higher the vapour pressure, the more volatile a liquid is.

Hence, 3 is false.

My take of this problem would be 2, 1, 4 being in that order.
1st fact: Vapour pressure increases with increasing of temperature.
2nd fact: Boiling occurs when the vapour pressure equals the surrounding pressure.

Hence the pressure inside the lamp must be high, so that the vapour pressure has to increase by a large amount before being able to reach the pressure, therefore 'pushing up' the boiling point.
Thus, conclusion 4.

Oh so, 3 is false and only number 4 is correct right?

Yeah.. I was confusing on these two answers.

Thank you , you make me understand