The escape of gas molecules through a tiny hole into a vacuum is called:

1. Two similar-sounding processes describe gas molecules moving. 2. A process involving movement of gaseous species similar to diffusion is effusion. 3. Effusion is the escape of gas molecules through a tiny hole, such as a pinhole in a balloon, into a vacuum. 4. Diffusion instead is spreading through another gas rather than escaping through a hole. _Source: OpenStax Chemistry 2e (CC BY 4.0), Ch 9 'Gases', sections 9.1-9.6_