Question

Barium sulfate, BaSO4, is a white crystalline solid that is insoluble in water. It is used by doctors to diagnose problems with the digestive system. Barium hydroxide, Ba(OH)2, is also a white crystalline solid and is used in wastewater treatment.​​​​​​​ How many more oxygen atoms are represented in the formula for barium sulfate than in the formula for barium hydroxide?

Answer 1

Barium Sulfate, BaSO4, has 4 oxygen atoms
Barium Hydroxide, Ba(OH)2, has 2 oxygen atoms, as there are two oxygen atoms in Hydroxide (OH)2

There are 2 more oxygen atoms in Barium Sulfate (4-2)