ch 11: thermodynamics

Thermo/ Dynamics

Temperature/ change or movement

What is Temperature?

A measure of the average kinetic energy of particles in an object.

Hot particles

Move faster as temperature increases.

Cold particles

Move slower as temperature decreases.

First Law of Thermodynamics

Energy cannot be created nor destroyed, only transformed.

Second Law of Thermodynamics

Energy flows from hot to cold; objects exchange energy until reaching equilibrium.

Conduction

Heat transfer through physical contact between objects of different temperatures.

Example of Conduction

A hot plate.

Convection

Heat transfer through movement of fluids (liquids and gases).

Example of Convection (liquid)

Boiling water.

Example of Convection (gas)

Oven.

Radiation

Heat transfer through electromagnetic waves.

Example of Radiation

Sunlight.

Temperature Change Dependents

Mass of the element/compound and specific heat of the element/compound.

Specific Heat Definition

The amount of energy needed to raise 1 gram of a substance by 1°C.

Lowest Specific Heat

Sand, requires less energy to heat.

Highest Specific Heat

Water, requires more energy to heat.

Specific Heat Dependents

Type of molecule, molecular arrangement, and molecular interaction.

Specific Heat Formula

q = mcΔT, where q = heat energy, m = mass, c = specific heat, ΔT = temperature change.

Heat Energy Formula

Q = m · C_p · ΔT.

Steps to Calculate ΔT

Determine Tf, determine Ti, then ΔT = Tf - Ti.

Interpreting Q: Positive Q

Heat energy is absorbed.

Interpreting Q: Negative Q

Heat energy is released.