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Жүктеу
#1 слайд
First law of
thermodynamics
Learning Objectives:
Explain the first law of
thermodynamics.
1 слайд
First law of thermodynamics Learning Objectives: Explain the first law of thermodynamics.
#2 слайд
Thermodynamics
•The study of processes in which
energy is transferred as heat and as
work.
•Important to define the system that we
are dealing with;
•Everything other than the system shall
be referred to as the “environment” or
“surroundings”.
2 слайд
Thermodynamics •The study of processes in which energy is transferred as heat and as work. •Important to define the system that we are dealing with; •Everything other than the system shall be referred to as the “environment” or “surroundings”.
#3 слайд
First law of thermodynamics
The change in internal energyΔU of a closed
system will be equal to the energy Q added to the
system minus the work W done by the system on
the surroundings.
ΔU = Q - W
The First Law of Thermodynamics is a statement of
energy conservation for thermodynamic systems.
∆U = Q - WQ : heat
∆U : change in internal energy
W: work
3 слайд
First law of thermodynamics The change in internal energyΔU of a closed system will be equal to the energy Q added to the system minus the work W done by the system on the surroundings. ΔU = Q - W The First Law of Thermodynamics is a statement of energy conservation for thermodynamic systems. ∆U = Q - WQ : heat ∆U : change in internal energy W: work
#4 слайд
Sign Convention (Very Important!)
The system is the gas, fluid, etc. you are
analyzing.
+Q means heat added to the system
-Q means heat removed from the system
+W means work done on the system
(compression)
-W means work done by the system
(expansion)
4 слайд
Sign Convention (Very Important!) The system is the gas, fluid, etc. you are analyzing. +Q means heat added to the system -Q means heat removed from the system +W means work done on the system (compression) -W means work done by the system (expansion)
#5 слайд
III. Problem solves
•A gas is kept in a cylinder that can be
compressed by pushing down on a piston. You
add 2500 J of heat to the system, and then you
push the piston 1.0 m down with a constant
force of 1800 N. What is the change in the gas’s
internal energy?
2500 J of heat is added to a system, and 1800 J
of work is done on the system. What is the
change in internal energy of the system?
3). Қандай да бір газдың көлемі 20 л. Оның кеңеюі
барысында 600 Дж жұмыс жасалған.
Газдың қысымы 40 кПа болса, соңғы көлемі
қандай? (Жауабы: 35 л)
5 слайд
III. Problem solves •A gas is kept in a cylinder that can be compressed by pushing down on a piston. You add 2500 J of heat to the system, and then you push the piston 1.0 m down with a constant force of 1800 N. What is the change in the gas’s internal energy? 2500 J of heat is added to a system, and 1800 J of work is done on the system. What is the change in internal energy of the system? 3). Қандай да бір газдың көлемі 20 л. Оның кеңеюі барысында 600 Дж жұмыс жасалған. Газдың қысымы 40 кПа болса, соңғы көлемі қандай? (Жауабы: 35 л)
#6 слайд
1
st
law of Thermodynamics Worksheet
Show your work.
1.What is thermodynamics?
2.What is internal energy?
3.State the first law of thermodynamics.
4.Calculate ∆U for each of the following cases:
•Q = + 51 kJ, W = - 15 kJ
•Q = + 100. kJ, W = - 65 kJ
•Q = - 65 kJ, W = - 20 kJ
1.Calculate ∆U for each of the following:
•Q = - 47 kJ, W = + 88 kJ
•Q = + 82 kJ, W = + 47 kJ
•Q = + 47 kJ, W = 0
1.A system releases 125 kJ of heat while 104 kJ of work is done on
the system. Calculate
the change in internal energy (in kJ).
6 слайд
1 st law of Thermodynamics Worksheet Show your work. 1.What is thermodynamics? 2.What is internal energy? 3.State the first law of thermodynamics. 4.Calculate ∆U for each of the following cases: •Q = + 51 kJ, W = - 15 kJ •Q = + 100. kJ, W = - 65 kJ •Q = - 65 kJ, W = - 20 kJ 1.Calculate ∆U for each of the following: •Q = - 47 kJ, W = + 88 kJ •Q = + 82 kJ, W = + 47 kJ •Q = + 47 kJ, W = 0 1.A system releases 125 kJ of heat while 104 kJ of work is done on the system. Calculate the change in internal energy (in kJ).
#7 слайд
Answer 1
st
law of Thermodynamics Worksheet
Show your work.
1.What is thermodynamics?
Thermodynamics is the study of processes in which energy is transferred as heat and as
work.
2.What is internal energy?
The sum total of all the energy of the molecules of the system.
3.State the first law of thermodynamics.
The change of internal energy of a closed system will be equal to the heat added to the
system minus the work done by the system.
4.Calculate ∆U for each of the following cases:
•Q = + 51 kJ, W = - 15 kJ ∆U = +36 KJ
•Q = + 100. kJ, W = - 65 kJ ∆U = +36 KJ
•Q = - 65 kJ, W = - 20 kJ ∆U = -85 KJ
1.Calculate ∆U for each of the following:
•Q = - 47 kJ, W = + 88 kJ ∆U = +41 KJ
•Q = + 82 kJ, W = + 47 kJ ∆U = +129 KJ
•Q = + 47 kJ, W = 0 ∆U = +47 KJ
1.A system releases 125 kJ of heat while 104 kJ of work is done on the system. Calculate
the change in internal energy (in kJ).
∆U = 21 KJ
7 слайд
Answer 1 st law of Thermodynamics Worksheet Show your work. 1.What is thermodynamics? Thermodynamics is the study of processes in which energy is transferred as heat and as work. 2.What is internal energy? The sum total of all the energy of the molecules of the system. 3.State the first law of thermodynamics. The change of internal energy of a closed system will be equal to the heat added to the system minus the work done by the system. 4.Calculate ∆U for each of the following cases: •Q = + 51 kJ, W = - 15 kJ ∆U = +36 KJ •Q = + 100. kJ, W = - 65 kJ ∆U = +36 KJ •Q = - 65 kJ, W = - 20 kJ ∆U = -85 KJ 1.Calculate ∆U for each of the following: •Q = - 47 kJ, W = + 88 kJ ∆U = +41 KJ •Q = + 82 kJ, W = + 47 kJ ∆U = +129 KJ •Q = + 47 kJ, W = 0 ∆U = +47 KJ 1.A system releases 125 kJ of heat while 104 kJ of work is done on the system. Calculate the change in internal energy (in kJ). ∆U = 21 KJ
#8 слайд
IV. Home task: Find 1 problem
of The First Law of
Thermodynamics.
Reflection:
Name one thing you would like
to know more
Give one thing which you find
difficult
Name one thing you liked most
8 слайд
IV. Home task: Find 1 problem of The First Law of Thermodynamics. Reflection: Name one thing you would like to know more Give one thing which you find difficult Name one thing you liked most
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