The phrase "different chemicals" refers to a variety or assortment of distinct substances that have different properties and characteristics. Full definition
Some people actually use human pain meds for dogs which can be very dangerous because the amount of different chemical in human medicine is different that the joint medicine for dogs. (usbones.com)
She's also testing different chemical compositions for the mold itself. (sciencedaily.com)
Conventional oil is made up of base oils blended with different chemicals to meet the needs of vehicle engines. (chryslerdodgeram.com)