The temperature at which a liquid becomes a gas is called the boiling point.

However, it's important to note that:

* Boiling point is specific to each substance. Water boils at 100°C (212°F), but ethanol boils at 78°C (173°F).

* Boiling point can be affected by pressure. Liquids boil at lower temperatures at lower pressures (like on a mountaintop).

So, there isn't one single temperature at which all liquids become gases.