AND OUR CONCLUSION IS..................
Q1: Lowest temperature : minus 273.16 degree C (459.69 degree F)
Q2: State of substance : gas
Q3: Experiment based on the relation between temperature of a substance and pressure of gas => lower the temperature of the gas confined in a fixed volume, its pressure and temperature will decrease in direct proportion, and the gas will become zero at minus 217.15 degree Celsius.
Q4: Volume gas thermometer used.
Q5:
Q6: The theoretically lowest temperature is 0.001 Kelvin, but it is impossible to reach the lower limit, which is absolute zero, meaning molecules of that substance stop moving.