Heat Transfer and Thermal Equilibrium - AP Chemistry

$\triangle T = T_{final} - T_{initial}$. Change equals final minus initial temperature values.

$\triangle U = q + w$. First law of thermodynamics relates energy, heat, and work.

A material's ability to conduct heat. Quantifies how well materials conduct thermal energy.

Radiation. Energy travels as photons without requiring matter.

Conduction. Direct contact transfers kinetic energy between molecules.

$c = \frac{500}{10 \times 5} = 10 \text{ J/g°C}$. Rearrange $q = mc\triangle T$ to solve for $c$.

It is the state when two objects reach the same temperature and no heat flows. Equal temperatures mean zero net heat flow between objects.

$C = mc$. Total heat capacity equals mass times specific heat capacity.

$q = mL_v$. Heat equals mass times latent heat of vaporization.

Convection. Bulk fluid motion transfers heat via density differences.

They must have the same temperature. No temperature difference means no driving force for heat flow.

The heat required to convert a liquid to gas at its boiling point. Energy needed to convert liquids to gas phase.

Heat flows from the hotter object to the cooler object. Heat naturally flows from high to low temperature regions.

$q = 100 \times 333 = 33300 \text{ J}$. Apply $q = mL_f$ for melting calculations.

The heat required to change the phase of a unit mass of a substance without temperature change. Energy needed for phase transitions at constant temperature.

J/g°C. Standard units for energy per mass per temperature change.

4.18 J/g°C. Standard reference value for aqueous solution calculations.

Heat capacity is the heat required to raise the temperature of an object by 1°C. Heat capacity depends on total mass, not per unit mass.

Final temperature is 40°C. Equal masses mix to the average of initial temperatures.

To measure the heat of chemical reactions or physical changes. Device isolates systems to measure thermal energy changes.

$q_{system} = -q_{surroundings}$. Heat lost by one equals heat gained by another.

J/kg. Energy per kilogram for phase change processes.

$\triangle U = q + w$. Internal energy change equals heat plus work done.

$q = mc\triangle T$. Heat equals mass times specific heat times temperature change.

The heat lost by hot objects equals the heat gained by cold ones. Energy conservation in thermal systems during heat exchange.

The temperature remains constant during a phase change. Energy goes to breaking bonds, not increasing kinetic energy.

The amount of heat required to raise the temperature of 1 g of a substance by 1°C. Measures the thermal energy needed per gram per degree Celsius.

Convection. Gas molecules move freely, enabling bulk heat transfer.

$q = mL_f$. Heat equals mass times latent heat of fusion.