Systems Flashcards
What is thermodynamics?
The science of energy changes involving work and heat.
What does the word ‘thermos’ mean?
Heat or energy.
What does the word ‘dynamics’ stand for?
Motion or change.
What types of thermodynamic systems exist?
- Open system
- Closed system
What is an open system?
A system that can exchange both energy and matter with its surroundings.
What is a closed system?
A system that can exchange only energy with its surroundings, not matter.
What are the primary parameters involved in thermodynamic systems?
- Temperature
- Pressure
- Volume
Define sensible heat.
Heat that causes a change in the temperature of an object.
What factors determine the amount of heat energy required to raise the temperature of a substance?
- Mass (m)
- Specific heat capacity (c)
- Temperature change (Δt)
What is the formula for calculating heat energy (Q)?
Q = m c Δt
What is the SI unit for quantity of heat?
Joule (J).
What is specific heat capacity?
The amount of heat required to change a unit mass of a substance by one unit of temperature.
What is the specific heat capacity of water?
4187 J kg−1 °C−1
Calculate the energy required to raise the temperature of 10 kg of steel from 20 to 420 °C.
1.92 MJ
Define latent heat.
The amount of energy needed to change the state of a material.
What is the specific latent heat of fusion?
Energy required for a change from solid to liquid.
What is the specific latent heat of vaporisation?
Energy required for a change from liquid to vapor.
What is the relationship between energy released and absorbed during phase changes?
The same amount of thermal energy is released per kilogram when a substance freezes as is required for it to melt.
What is the formula for calculating the quantity of thermal energy (Q) required to change the state of a substance?
Q = m h
What is the SI unit for quantity of energy?
Joule (J).
What is the specific latent heat required to melt copper?
3850 kJ kg−1
Calculate the quantity of latent heat required to melt 15 kg of copper.
57.75 kJ
