Heat Transfer, Specific Heat, Work, Calorimetry, and Variable Heat Capacity

All flashcards

What does $Q=mc\Delta T$ calculate?

Heat transferred when mass $m$ changes temperature by $\Delta T$ without a phase change, assuming constant specific heat $c$.

Which quantities are state variables, and which describe energy transfer?

Temperature and internal energy are state variables; heat and work describe energy transferred during a process.

What is a calorimeter?

A container designed to limit heat transfer between its contents and the surroundings.

How is heat calculated when specific heat varies with temperature?

Use $Q=m\int_{T_1}^{T_2}c(T)\,dT$.

What does the low-temperature Debye model predict for many solids?

Their specific heat is approximately proportional to the cube of temperature: $c\propto T^3$.

Quiz questions

1. How can friction raise the temperature of a material without heat flowing into it from a hotter object?Answer: It converts organized mechanical energy into microscopic energy.
2. Which statement correctly distinguishes heat and work from temperature and internal energy?Answer: Heat and work describe energy transfers; temperature and internal energy are state variables.
3. For a thermally isolated collection of objects, what is the sum of their signed heat transfers?Answer: $\sum_i Q_i=0$
4. In an insulated mixture with no phase change or external energy transfer, where does the common final temperature generally lie?Answer: Between the objects’ initial temperatures.
5. Why can a gas require different specific-heat values in different heating conditions?Answer: Its specific heat can depend on whether pressure or volume is held constant.