Mastering Thermal Properties of Matter: Formulas, Traps & Exam Strategy | ExamiFly

Heat capacity ($C$) is the amount of heat required to raise the temperature of an entire body by $1^\circ C$ (or $1 K$). Its unit is $J/K$ or $cal/^\circ C$. Specific heat capacity ($c$) is the amount of heat required to raise the temperature of a unit mass of a substance by $1^\circ C$ (or $1 K$). Its unit is $J/(kg \cdot K)$ or $cal/(g \cdot ^\circ C)$. So, $C = mc$, where $m$ is the mass of the body. Specific heat is an intrinsic property of the material, while heat capacity depends on both the material and its mass.

Water's high specific heat ($c_w = 1 \text{ cal/g}^\circ C$ or $4200 \text{ J/kg}^\circ C$) is due to its strong hydrogen bonding. A significant amount of energy is needed to break these bonds before the kinetic energy of molecules can increase, leading to a temperature rise. This has profound implications: it moderates Earth's climate, making coastal areas milder, and makes water an excellent coolant in industrial processes and biological systems.

Conduction involves heat transfer through direct contact, primarily in solids, without actual movement of matter (e.g., heat flowing through a metal rod). Convection involves heat transfer through the actual movement of fluid (liquid or gas) particles, creating currents (e.g., boiling water, air conditioning). Radiation involves heat transfer via electromagnetic waves, requiring no medium (e.g., heat from the sun, warmth from a fire).