Butane is a hydrocarbon that exists as a gas at room temperature and pressure. However, the butane used in some cigarette lighters is stored as a liquid. This can be explained by understanding the concepts of pressure and temperature in relation to the state of matter.
When butane is under normal atmospheric pressure, its boiling point is about -0.5 degrees Celsius (31.1 degrees Fahrenheit). This means that at room temperature (approximately 20-25 degrees Celsius), butane would naturally exist as a gas. However, in a lighter, butane is stored under higher pressure. This increased pressure causes the butane to change its state from gas to liquid.
When you press the button on the lighter, this release of pressure allows the liquid butane to vaporize quickly, turning back into gas and producing the flame. This is a common principle used in many pressurized gas containers, where a gas can be stored in liquid form until it is released under lower pressure.
In summary, butane is a gas at room temperature due to its boiling point, but when it is stored under pressure in a lighter, it remains in a liquid state. Once released, the pressure drops and the liquid transforms back into gas, allowing it to ignite and produce a flame.