19 Questions
What is the law that states mass is conserved and not created or destroyed?
First Law of Thermodynamics
In a steady-state, steady-flow process with multiple inlets and multiple outlets, what form does the energy balance take?
Rate basis
Which type of systems can be considered as special forms of open systems?
Closed systems
In a steady-state, steady-flow single inlet, single outlet open system, what is the mass flow rate term equal to?
$0$
What is the general first law of thermodynamics also known as?
Conservation of Energy
Which principle asserts that closed systems do not exchange matter with their surroundings?
First Law
What does the Zeroth Law of Thermodynamics state?
If two systems are at the same time in thermal equilibrium with a third system, they are in thermal equilibrium with each other.
Who first formulated and labeled the Zeroth Law of Thermodynamics?
R.H. Fowler in 1931
What is the function of a thermocouple in temperature measurement?
Detects a difference in electrical potential between two conductors of dissimilar materials
Why is the Zeroth Law of Thermodynamics called 'zeroth'?
Because it should have preceded the first and second laws of thermodynamics logically
What role does a thermometer's thermometric substance play?
Shows changes in properties due to heat interactions
In temperature measurement, why are two systems considered to be in thermal equilibrium according to the Zeroth Law of Thermodynamics?
When they are at the same temperature as a third system
According to the First Law of Thermodynamics, what is the relationship between work and heat in a system?
They are directly proportional.
What is the main principle behind the First Law of Thermodynamics?
Energy conversion leads to a constant total energy.
In a closed system, the change in internal energy (∆E) is equal to what combination of energy changes?
∆P∆E + ∆K∆E + ∆U + ∆(PV)
What is the formula for determining the enthalpy (H) of an ideal gas using the First Law?
H = q + w
In determining the internal energy of an ideal gas using the First Law, what does the term qv represent?
Heat transfer at constant volume
What does the First Law of Thermodynamics state about the conservation of mass?
Mass is conserved similar to energy.
What do ∆PE and ∆KE represent in the context of the First Law of Thermodynamics?
Changes in potential and kinetic energy
Study Notes
First Law of Thermodynamics
- The First Law of Thermodynamics, also known as the Law of Conservation of Energy, states that energy cannot be created or destroyed, only converted from one form to another.
- The law is often mathematically expressed as ΔE = Q - W, where ΔE is the change in total energy of the system, Q is the heat added to the system, and W is the work done on the system.
Systems
- A closed system is a system where no mass is exchanged with the surroundings, but energy can be exchanged in the form of heat and work.
- An open system is a system where both mass and energy can be exchanged with the surroundings.
Energy Forms
- Kinetic energy (KE) is the energy of motion.
- Potential energy (PE) is the energy of position or stored energy.
- Internal energy (U) is the total energy of the system, including kinetic energy, potential energy, and other forms of energy.
- Enthalpy (H) is a measure of the total energy of a system, including internal energy and the energy associated with the pressure and volume of a system.
First Law of Thermodynamics for Closed and Open Systems
- For a closed system, ΔE = Q - W, where ΔE is the change in internal energy of the system.
- For an open system, ΔE = Q - W + ΔEPE, where ΔEPE is the change in potential energy of the system.
Applications of the First Law of Thermodynamics
- Compression of gas in a closed system: Q - W = ΔU
- Ideal gas: dh = du + pdv, where dh is the change in enthalpy, du is the change in internal energy, pdv is the work done on the system.
Heat Transfer and Specific Heat Capacity
- Heat transfer (Q) can be calculated using the formula Q = mcΔT, where m is the mass of the substance, c is the specific heat capacity, and ΔT is the temperature difference.
- Specific heat capacity (c) is the amount of heat energy required to raise the temperature of a unit mass of a substance by one degree Celsius.
Conservation of Mass
- The law of conservation of mass states that mass is neither created nor destroyed, only converted from one form to another.
Time Rate Form of the First Law
- The time rate form of the First Law of Thermodynamics is a mathematical expression of the law that describes the rate of energy exchange between a system and its surroundings.
Zeroth Law of Thermodynamics
- The Zeroth Law of Thermodynamics states that if two systems are in thermal equilibrium with a third system, they are also in thermal equilibrium with each other.
- The Zeroth Law is the basis of temperature measurement and is used to define the temperature of a system.
Test your knowledge on the First Law of Thermodynamics, which states that energy cannot be created or destroyed, only converted from one form to another. This law explains the relationship between heat, work, and energy in a system.
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