what is atm in chemistry

ATM in chemistry stands for "Atmosphere," which is a unit of pressure. It represents the standard atmospheric pressure exerted by the weight of the air at sea level. This unit is commonly used when studying gases, particularly with the Ideal Gas Law (PV=nRT), to understand how pressure affects chemical reactions and gas behaviour. One standard atmosphere (1 atm) is precisely defined as 101,325 Pascals (Pa), which is also equivalent to 760 millimeters of mercury (mmHg) or 760 torr.