Final answer:
One formula unit of calcium hydrogen sulfate contains 8 oxygen atoms, as it includes two sulfate ions, each contributing 4 oxygen atoms.
Step-by-step explanation:
The student has asked about the number of oxygen atoms in a formula unit of calcium hydrogen sulfate. Calcium hydrogen sulfate has the chemical formula Ca(HSO4)2. To find the number of oxygen atoms, we look at the sulfate ion, which is SO42-, and remember that there are two sulfate ions in each formula unit of calcium hydrogen sulfate. Therefore, we have 4 oxygen atoms from one sulfate ion, multiplied by 2 because there are two sulfate ions, equalling 8 oxygen atoms in total.