To solve this question, we need to refer to the molarity formula: molarity=moles/volume(L). First, make sure to convert the volume in milliliters to liters by moving the decimal point three times to the left (100 mL is equal to 0.1 liter). Then, we can plug in the molarity and the volume to solve for the number of moles: 0.250=moles/0.1L. When you cross multiply, you get moles=0.025 which is the final answer.
