Final answer:
Before using a recovery cylinder, check for leaks and ensure it's safe to contain gases. Do not heat the cylinder, add acid to water (not vice versa), and smell chemicals safely by wafting.
Step-by-step explanation:
Before using an empty recovery cylinder, which refers to a cylinder used to recover refrigerant from HVAC systems, you should ensure that it is safe and ready to contain the gases effectively. The cylinder should be checked for leakage to ensure that the gas is not leaking out. It is also important to remember that the cylinder does not significantly change in size as it warms during the recovery process. Safety protocols must be followed, including making sure never to add water to acid (always add the acid to water) and to never heat thick glassware such as a measuring cylinder as it may break. Moreover, when dealing with chemicals, proper smelling techniques should be applied - do not smell directly from the container but rather place it on the laboratory bench and waft the air towards your nose.