Final answer:
The total number of oxygen atoms in the compound Na₂B₄O₇·10 H₂O is 17, as it contains 7 oxygen atoms in the borate ion part and 10 oxygen atoms in water molecules.
Step-by-step explanation:
The question asks for the total number of oxygen atoms in the compound Na₂B₄O₇·10 H₂O. To calculate this, we should count the oxygen atoms in both parts of the compound: the borate ion ·Na₂B₄O₇ and the water of hydration (10 H₂O).
In the borate ion (Na₂B₄O₇), there are 7 oxygen atoms. Since there is no subscript outside the parentheses, we know these represent 7 individual oxygen atoms.
In the water of hydration (10 H₂O), there is 1 oxygen atom for each water molecule. Since we have 10 water molecules, that is 10 oxygen atoms total.
Adding both parts together, 7 oxygen atoms from the borate ion and 10 oxygen atoms from water of hydration, gives us a total of 17 oxygen atoms represented in the compound Na₂B₄O₇·10 H₂O. Therefore, the answer is (b) 17.