2.1.1 Basic terms in thermodynamics l.System(系统)and surroundings(环境) System:the specific part of the universe we are studying Surroundings:the rest of the universe outside the System,normally referring to the closely related moiety Open system:a system can exchange mass and energy with its surroundings Closed system:a system exchanges energy but not matter with its surroundings Isolated system:a system exchange neither mass nor energy with its surroundings System：the specific part of the universe we are studying Surroundings：the rest of the universe outside the System, normally referring to the closely related moiety Open system: a system can exchange mass and energy with its surroundings Closed system: a system exchanges energy but not matter with its surroundings Isolated system: a system exchange neither mass nor energy with its surroundings 2.1.1 Basic terms in thermodynamics 1. System (系统) and surroundings (环境)