The molar mass of carbon dioxide (CO2) is 44.01 g/mol. This means that 1 mole of carbon dioxide has a mass of 44.01 grams. To find the number of moles of carbon dioxide in 1.66 grams, we divide the mass by the molar mass:

1.66 g / 44.01 g/mol = 0.0377 mol

Now, we can use the ideal gas law to calculate the volume of 0.0377 mol of carbon dioxide at a temperature of 25°C and a pressure of 1 atm. The ideal gas law is:

PV = nRT

where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.

At a temperature of 25°C, which is 298.15 K, and a pressure of 1 atm, the ideal gas constant has a value of 0.08206 L atm / mol K. Substituting these values into the ideal gas law, we get:

V = nRT / P

V = (0.0377 mol) x (0.08206 L atm / mol K) x (298.15 K) / (1 atm)

V = 0.904 L

Therefore, the volume of 1.66 grams of carbon dioxide at a temperature of 25°C and a pressure of 1 atm is 0.904 L.