The difference between closed containers and open containers in chemical reactions is as follows

　　A closed container is a container that is isolated from the outside world and does not leak. An open container is a container that has some connection with the outside world.

　　There are two types of closed containers at the secondary school level:

　　1. It is an isochoric closed container with constant volume

　　2. It is an isobaric closed container with constant pressure. There is no gas exchange between the closed container and the outside world.

　　For example, experiments to prove the law of conservation of mass can still draw correct conclusions if they are conducted in closed containers with or without the participation of gases.