Chapter U3.5, Problem 1E

Interpretation Introduction

Interpretation : Absolute zero is to be defined and explained why it is a hypothetical temperature.

Concept Introduction : Temperature is degree of hotness or coldness. On Earth the coldest place is Antarctica with a temperature of -89⁰C. Temperatures as low as -235⁰C have been recorded by researchers on the surface of Triton, a moon of Neptune.

Answer to Problem 1E

Absolutezero is the lowest temperature possible where the volume of a substance would decrease to zero. It is found out to be equal to -273.15⁰C as the temperature at which substances would have zero volume.

It is considered a hypothetical temperature because zero volumeor negative volume does not make much sense as it is impossible to achieve this temperature where the atoms would not have any motion.

Explanation of Solution

Matter responds to change in temperature by displaying change in volume. Generally increase in temperature causes matter to expand while cooling makes the matter contract. This property of matter is used to measure temperature.

With a decrease in temperature volume of most substances also decreases. Hypothetically, the lowest temperature possible would be something that would correspond to a volume of zero.

The lowest temperature possible is called absolute zero. This is found out to be equal to -273.15⁰C as the temperature at zero volume.

The volume of most substances decease with a decrease in temperature but there is a limit to how much a substance can shrink. A negative volume does not make much sense. So absolute zero is considered a hypothetical temperature. As the temperature is lowered, a gas would actually condense to liquid and then to solid. Scientists believe that at absolute zero, the atoms would stop moving.

Conclusion

As the temperature is lowered a gas would actually condense to liquid and then to solid. So zero volume is a property that is still a hypothesis.