Unit 5: Heat Conduction and Calorimeter

Flashcards covering the properties of heat, laws of thermodynamics, mechanisms of heat transfer, heat capacity concepts, and thermal expansion formulas.

Heat

A form of energy characterized by the spontaneous transfer of energy from a hotter body to a colder body.

Temperature

A physical quantity that measures the average kinetic energy of particles of the substance.

Thermal expansion

The change in size of matter due to a change in temperature.

First law of Thermodynamics

A law of physics stated as the equation $\Delta U = \Delta Q + \Delta W$.

Second law of thermodynamics

The principle stating that "The spontaneous transfer thermal energy from a cooler body to a hotter body is impossible."

Thermal equilibrium

A state reached when the temperature of two bodies is equal, resulting in no net heat flow.

Conduction

The transfer of heat from one object to another by the collision of neighbouring particles; no actual drift of molecules occurs in the direction of heat flow.

Convection

The transfer of heat between two bodies by current of moving gas or fluids, occurring only in fluids.

Radiation

Heat transfer facilitated through electromagnetic radiation that does not require a medium to carry it.

Heat capacity ($C$)

The amount of heat required to change the temperature of a given amount of matter by $1^\circ\text{C}$ or by $1\,\text{K}$, expressed as $C = \frac{\Delta Q}{\Delta T}$.

SI unit of heat capacity

The Standard International unit is $\text{J/K}$, where $1\,\text{J/K} = 1\,\text{J/}^\circ\text{C}$.

Specific heat capacity ($c$)

The amount of heat absorbed or released by $1\,\text{kg}$ of an object to change its temperature by $1^\circ\text{C}$ or by $1\,\text{K}$, expressed as $c = \frac{\Delta Q}{m\Delta T}$.

SI unit of specific heat capacity

The Standard International unit is $\text{J/kg K}$, where $1\,\text{J/kg K} = 1\,\text{J/kg }^\circ\text{C}$.

Linear Expansion

A change in length along one dimension due to a change in temperature, calculated using $\Delta L = \alpha L_0 \Delta T$.

Linear coefficient of thermal expansion ($\alpha$)

A unique property of a substance representing how much it expands per unit of temperature change, measured in $^\circ\text{C}^{-1}$ or $\text{K}^{-1}$.

Area expansion

The change in surface area due to temperature change, calculated as $\Delta A = \gamma A_0 \Delta T$, where $\gamma = 2\alpha$.

Volume expansion

The change in volume of a substance due to temperature change, calculated as $\Delta V = \beta V_0 \Delta T$, where $\beta = 3\alpha$.