Final answer:
Escape velocity is the minimum velocity required for an object to overcome the gravitational pull of a planet; for Earth, it is about 11.2 km/s. It is at the speed where an object's total energy at an infinite distance from the planet's center would be zero. The escape velocity differs for other celestial bodies like the Moon, where it is only 2.38 km/s.
Step-by-step explanation:
Understanding Escape Velocity
The term escape velocity refers to the minimum speed that a molecule or any object needs to achieve in order to overcome the gravitational pull of a planet. It represents the speed at which the total energy (kinetic plus potential) of the object would be zero when reaching an infinite distance from the center of the planet, effectively escaping the gravitational field without further propelling thrust.
At the surface of Earth, escape velocity is approximately 11.2 km/s. Objects, including rockets or gas molecules like helium or oxygen, must reach or exceed this velocity to escape Earth's gravity. For instance, to calculate at what temperature oxygen molecules would have a root-mean-square velocity equal to the escape velocity, a specific calculation using the molar mass of oxygen is required.
Similarly, the escape velocity from the Moon is lower, only about 2.38 km/s, due to its smaller mass and gravitational pull. Therefore, for a hydrogen molecule to escape the Moon's gravity, it would need to reach this velocity, which again relates to a specific temperature calculation based on the molar mass of hydrogen.