What is the best safety approach when working with unknown chemical substances? Select one: Assume that any substance distributed to lab participants is non-toxic and not a safety risk. Read the procedure and try to guess what the unknown substance is, then review its specific safety information. Assume that the substance is hazardous. Always wear appropriate PPE and take steps to prevent contact. Do not begin working with a substance unless you know exactly what it is.

Assume that the substance is hazardous. Always wear appropriate PPE and take steps to prevent contact.

Explanation:

When working with chemicals, a sound safety policy involving the use of chemicals should be established and maintained. This will help in safeguarding lives, properties and the environment.

The best safety approach when working with unknown chemical substances is to assume that the substance is hazardous and always wear appropriate PPE and take steps to prevent contact.

Since the substance is unknown, the best thing the person can do is to assume that it's harmful and hazardous and therefore take necessary precautions. The individual can put on laboratory coats, protective glasses, gloves etc. This is vital in order to prevent accidents from happening.

fe 55.85 g/mol and h2o 18.02 g/mol.