Final answer:
The volume of a Helium-filled balloon will increase from 35.0 L to approximately 38.1 L as the temperature rises from 20° C to 45° C, according to Charles's Law.
Step-by-step explanation:
The relationship between the temperature and volume of a gas at constant pressure is described by Charles's Law, which states that the volume of a gas is directly proportional to its temperature on an absolute scale (Kelvin). We can determine the new volume of the balloon using the formula V1/T1 = V2/T2, where V1 is the initial volume, T1 is the initial temperature, V2 is the final volume, and T2 is the final temperature. Converting the temperatures from Celsius to Kelvin by adding 273.15 to each, we have T1 = 293.15 K and T2 = 318.15 K. Given the initial volume (V1) of 35.0 L at the initial temperature (T1) of 293.15 K, and the final temperature (T2) of 318.15 K, the equation to find the new volume (V2) is: 35.0 L / 293.15 K = V2 / 318.15 K. Solving for V2 gives: V2 = (35.0 L × 318.15 K) / 293.15 K, V2 ≈ 38.1 L. Thus, the new volume of the balloon when the temperature is 45° C is approximately 38.1 liters.