To determine the temperature to which the gas must be lowered in order to reduce its volume to half, we can make use of Charles's Law, which states that the volume of a gas is directly proportional to its temperature when pressure and amount of gas remain constant.
According to the problem, the initial volume of the gas (V1) is 180 ml, and the final volume (V2) is half of the initial volume (V1/2 = 180 ml / 2 = 90 ml).
Now, let's set up the equation using Charles's Law:
V1 / T1 = V2 / T2
Substituting the known values:
180 ml / (37°C + 273.15) K = 90 ml / T2
Simplifying the equation:
180 / (37 + 273.15) = 90 / T2
180 / 310.15 = 90 / T2
Cross-multiplying:
180 * T2 = 90 * 310.15
T2 = (90 * 310.15) / 180
T2 ≈ 155.08°C
Therefore, the gas must be lowered to approximately 155.08°C (rounded to two decimal places) in order to reduce its volume to half (90 ml).