Calculate the osmotic pressure of a solution containing 19.45 mg of hemoglobin in 16.8 mL of solution at 18 °C. The molar mass of hemoglobin is 6.5×10^4 g/mol. Assume the solution behaves ideally and use R = 0.0821 L·atm/mol·K.

Convert the volume of the solution from milliliters to liters by dividing by 1000, as the gas constant R is given in L·atm/mol·K.

Use the formula for osmotic pressure: \( \Pi = \frac{nRT}{V} \), where \( n \) is the number of moles, \( R \) is the gas constant, \( T \) is the temperature in Kelvin, and \( V \) is the volume in liters. First, convert the temperature from Celsius to Kelvin by adding 273.15.