Final answer:
The nurse should administer 2 tablets of acetaminophen, each containing 325 milligrams.
Step-by-step explanation:
To determine the number of milligrams the nurse should administer, we multiply the number of tablets by the dosage per tablet. In this case, the client is to receive 0.65 grams, which is equivalent to 650 milligrams, every 6 hours. Since each tablet contains 325 milligrams of acetaminophen, the nurse should administer 2 tablets.