heat Flashcards
What is heat?
Total kinetic and potential energies of the molecules in an object
Heat is a form of energy transferred due to a temperature difference.
What is the SI unit of heat?
Joule
A more common unit is the calorie (cal), where 1 cal = 4.184 J.
What is temperature?
Measure of the average kinetic energy of all the particles in the object.
What are the three temperature scales?
- Celsius (°C)
- Fahrenheit (°F)
- Kelvin (K)
What is a thermometer?
A device that measures temperature by using a physical property that changes with temperature.
How does heat transfer through conduction?
By molecular collision without a net movement of the body.
What is convection?
Movement that transfers heat within fluids.
What is radiation?
Transfer of energy by electromagnetic waves.
What is specific heat capacity?
Energy required to change the temperature of 1 kg of a substance by 1°C.
What is calorimetry?
An experimental procedure used to measure the energy transferred from one substance to another as heat.
What does the law of conservation of energy state in calorimetry?
Heat gain + heat loss = 0.
What is latent heat of fusion?
The amount of heat needed to change the unit mass of a substance from solid to liquid at its melting point.
What is latent heat of vaporization?
The amount of heat needed to change the unit mass of a substance from liquid to gas at its boiling point.
What is thermal expansion?
The tendency of matter to change in length, area, or volume in response to temperature alterations.
What are the types of thermodynamic systems?
- Open System
- Closed System
- Isolated System
What does the first law of thermodynamics state?
When heat is added to a system, some remains in the system, increasing its internal energy, while the rest leaves as work.
What is the Kelvin-Planck statement of the second law of thermodynamics?
No heat engine can completely convert heat into work.
What does the Clausius statement of the second law of thermodynamics state?
Heat flows naturally from hot objects to cold objects, never the reverse.
What is the entropy statement of the second law of thermodynamics?
Entropy of the universe does not change in reversible processes and increases in irreversible processes.
Fill in the blank: The specific heat capacity is expressed mathematically as _______.
cp=Q/(mΔT)
What is the average human body temperature in degrees Fahrenheit?
98.6 degrees Fahrenheit.
What happens during phase change regarding temperature?
Adding/removal of heat does not always result in temperature change.
Which type of heat transfer does NOT require matter?
Radiation.
What is the formula to calculate the heat needed for temperature change?
Q = m * cp * ΔT
