In a student experiment, a constant-volume gas thermometer is calibrated in dry ice (-78.5 C). The separate pressures are 0.900 atm and 1.635 atm. (a) What value of absolute zero in degrees Celsius does the calibration yield? What pressures would be found at (b)the freezing and (c) the boiling points of water? Hint: Use the linear relationship P = A + BT, where A and B are constants.