A healthcare provider prescribes a maintenance dose of 2 grams per hour of intravenous magnesium sulfate for a client with preeclampsia. The IV bag contains 20 grams of magnesium sulfate in 500 mL of 5% dextrose in water. How many mL/hour should the nurse set the infusion pump to deliver? (Note: This is a medical math, so no options are provided.)