3. A scientist used a filter weighing 4.020 grams to collect particles. After pumping 750 mL of air through the filter, it weighed 4.031 grams. What was the concentration of particle mass in the
processed air, in milligrams per liter (mg/L)?

Answer    "a salt" would be the best answerexplanationsalts can be defined as ionic compounds that are neither acids nor bases. nacl is an example of a salt, and its ionic.an enzyme is an organic compound which is covalently bonded, not ionically bonded.acids are generally held together by covalent bondsan element does not need any bonds to exist

It's potassium i believe