Question

Difficulty: HardTemperature Scales and Thermometric Properties

A thermometric property XX of a system has a value of 15.0units15.0\,\text{units} at the ice point (0C0^\circ\text{C}) and 75.0units75.0\,\text{units} at the steam point (100C100^\circ\text{C}). If the thermometric property is measured as 33.0units33.0\,\text{units} when immersed in a chemical bath, what is the temperature of the bath on the absolute thermodynamic scale?

  1. 303K303\,\text{K}Answer
  2. B
    317K317\,\text{K}
  3. C
    297K297\,\text{K}
  4. D
    30K30\,\text{K}

Answer

303K303\,\text{K}
The temperature of the bath on the Celsius scale is found by taking the ratio of the change in thermometric property from the ice point to the total fundamental interval: 33.015.075.015.0×100C=1860×100=30C\frac{33.0 - 15.0}{75.0 - 15.0} \times 100^\circ\text{C} = \frac{18}{60} \times 100 = 30^\circ\text{C}. Converting this temperature to the absolute (Kelvin) scale requires adding 273K273\,\text{K}, yielding 30+273=303K30 + 273 = 303\,\text{K}.

Step-by-Step Solution

1
Identify the given thermometric values for the fixed points and the unknown state
X0=15.0unitsX_0 = 15.0\,\text{units} (ice point, 0C0^\circ\text{C}), X100=75.0unitsX_{100} = 75.0\,\text{units} (steam point, 100C100^\circ\text{C}), and XT=33.0unitsX_T = 33.0\,\text{units}
Linear thermometric interpolation requires defining the fixed reference points and the measured property value.
2
Calculate the temperature on the Celsius scale using the linear scale formula
θ=XTX0X100X0×100C=33.015.075.015.0×100=18.060.0×100=30C\theta = \frac{X_T - X_0}{X_{100} - X_0} \times 100^\circ\text{C} = \frac{33.0 - 15.0}{75.0 - 15.0} \times 100 = \frac{18.0}{60.0} \times 100 = 30^\circ\text{C}
The temperature change relative to the fundamental interval determines the position on the Celsius scale.
3
Convert the temperature from degrees Celsius to Kelvin
T=θ+273=30+273=303KT = \theta + 273 = 30 + 273 = 303\,\text{K}
The absolute thermodynamic scale (Kelvin) is shifted from the Celsius scale by adding 273K273\,\text{K}.

Key Concept

Linear interpolation of temperature using thermometric properties and conversion to the absolute scale
Estimated Time:2m 0s
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