Thermochemistry is the branch of chemistry dealing with reciprocity heat with chemical reactions or with physical changes of state. In general, is the application of thermochemical for chemical thermodynamics.Thermochemistry is the synonym of chemical thermodynamics.The main objective is the formation of chemical thermodynamics criteria for the determination of the terms or spontaneity possibility of transformation required. [1] In this way, estimates used thermochemical energy changes that occur in the following processes:
chemical reaction
phase change
forming solutionThermochemistry is primarily concerned with the function of the following conditions are confirmed in thermodynamics:
Energy in the (U)
Energy in (E) is the total kinetic energy (Ek) and potential energy (Ep) in the system. Therefore, energy can be defined by the equation E = Ek + Ep. However, because the kinetic energy and potential energy in a system can not be measured, then the energy in a system also can not be determined, which can be determined is the energy change in a system.The change in energy can be determined by measuring the heat (q) and work (w), which would arise if the system reacts. Therefore, changes in the energy equation formulated E = q + w.If the system absorbs heat, then q is positive. If the system issued a heat, then q is negative.If the system does work, then the formula w is positive. If the system is working by lingungan, then w is negative.So if a system absorbs heat from the environment by 10 kJ, and the system also does work at 6 kJ, the energy change in his will of 16 kJ.Energy changes in the value 0 if the number of the incoming heat equal to the amount of work done, and if the heat released is equal to the work imposed on the system. That is, no changes in energy that occur in the system.
Enthalpy (H).
Adala enthalpyh term in thermodynamics that states the amount of internal energy of a thermodynamic system plus the energy used to do work. Enthalpy can not be measured, which can be calculated is the value changes.Mathematically, the enthalpy change can be formulated as follows:ΔH = ΔU + PΔVwhere:
H = enthalpy of the system (joules)
U = internal energy (joules)
P = pressure of the system (Pa)
V = system volume (m3)
Entropy (S)
Thermodynamics (Greek: thermos = 'hot' and dynamic = 'change') is the physics of energy, heat, work, entropy and the spontaneity of processes. Thermodynamics closely related to statistical mechanics where many thermodynamic relations derived.While dealing with a process in which systems exchange matter or energy, classical thermodynamics is not related to the speed of the process, called kinetic. For this reason, use of the term "thermodynamics" usually refers to the thermodynamic equilibrium. In this connection, a key concept in thermodynamics is kuasistatik process, the idealized, the "super slow". Time-dependent thermodynamic processes studied in non-equilibrium thermodynamics.Since thermodynamics is not concerned with the concept of time, it has been proposed that the thermodynamic equilibrium should be called thermostatic.Laws of thermodynamics truth is very common, and these laws are not dependent on the details of the interactions or the systems being studied. This means they can be applied to a system in which a person does not know anything but the balance of energy and matter transfer between them and the environment. Examples include estimates Einstein spontaneous emission in the 20th century and current research on the thermodynamics of black objects.Everyday experience shows that a pond does not freeze in the summer. If a hot object interacts with a cold object, it would not be that hot body is getting hotter and cold items colder, although these processes are not breaking the law of conservation of energy expressed as the first law of thermodynamics.The second law of thermodynamics relates to whether these processes are considered to be the first law abiding principle, occur or do not occur in nature. The second law of thermodynamics as expressed by the Clausius said,? For a cyclical machine it is not possible to produce other effects, in addition to continuously convey heat from an object to another object at a higher temperature. "When viewed Carnot cycle, the cycle consists of four hypotheses irreversible processes: isothermal expansion with the addition of heat, adiabatic expansion, isothermal compression with heat release and adiabatic compression, if the integral of a quantity circling any closed path is zero, then the quantity is the state variable , has a value that is only a characteristic of the state of the system, no matter what the situation is. State variable in this case is the entropy. Gayut entropy change only the initial state and the final state and no gayut process connecting the initial state and the final state of the system.The second law of thermodynamics in the concept of entropy says, "A natural process that began in one state of equilibrium and end up in a state of equilibrium others will move in the direction that causes the entropy of the system and its environment grows".If the entropy associated with the disorder, the statement of the second law of thermodynamics in the natural processes tend to increase equivalent states, and the chaos of the system tends to increase.In the free expansion, the gas molecules occupy the whole space box is more chaotic than when the gas molecules occupy half the space box. If two objects have different temperatures T1 and T2 interact, thereby achieving a uniform temperature T, it can be said that the system becomes more chaotic, in a sense, the statement "all of the molecules in the system corresponds to the temperature T is weaker when compared tostatement of all the molecules in the body corresponds to a temperature T1 and object B corresponds to the temperature T2 ".In the statistical mechanics, the relationship between entropy and chaos parameters are, pers. (1):S = k log wwhere k is the Boltzmann constant, S is the entropy of the system, w is a parameter chaos, the possibility of its being of the system relative to all the circumstances that may be occupied.If the terms change in entropy of an ideal gas in isothermal expansion, where the number of molecules and the temperature has not changed while the volume is greater, then the possibility of a molecule can be found in the area of volume V is proportional to V, ie, the larger V, the greater the opportunity for discovered molecule in V.Possibility of finding a single molecule in V are, pers. (2):W1 = c Vwhere c is a constant. The chances of finding N molecules simultaneously in the volume V is N times the result of w. Namely, the possibility of a state consisting of N molecules in volume V is, pers. (3):w = W1N = (CV) N.If equation (3) substituted into (1), the difference in entropy of an ideal gas in an isothermal expansion process where the temperature and number of molecules does not change, it is worth positive. This means that the entropy of an ideal gas in an isothermal expansion process is increased.Statistical definition of the entropy, ie, equation (1), connect an overview of thermodynamics and statistical mechanics description which allows to put the second law of thermodynamics to statistical base. Direction in which natural processes will occur toward higher entropy is determined by the laws of probability, ie, toward a state more likely. In this case, the state of equilibrium is a state where the maximum entropy in thermodynamics and circumstances are most likely to be statistically. But the fluctuations, ie Brownian motion, can occur around the equilibrium distribution. From this perspective, it is essential that the entropy will increase in every spontaneous process. Entropy can sometimes be reduced. If you wait long enough, the situation is not likely to happen once: the water in the pond suddenly froze on a hot summer day or a local vacuum occurs suddenly in a room. The second law of thermodynamics shows the direction events are most likely, not just possible events.
chemical reaction
phase change
forming solutionThermochemistry is primarily concerned with the function of the following conditions are confirmed in thermodynamics:
Energy in the (U)
Energy in (E) is the total kinetic energy (Ek) and potential energy (Ep) in the system. Therefore, energy can be defined by the equation E = Ek + Ep. However, because the kinetic energy and potential energy in a system can not be measured, then the energy in a system also can not be determined, which can be determined is the energy change in a system.The change in energy can be determined by measuring the heat (q) and work (w), which would arise if the system reacts. Therefore, changes in the energy equation formulated E = q + w.If the system absorbs heat, then q is positive. If the system issued a heat, then q is negative.If the system does work, then the formula w is positive. If the system is working by lingungan, then w is negative.So if a system absorbs heat from the environment by 10 kJ, and the system also does work at 6 kJ, the energy change in his will of 16 kJ.Energy changes in the value 0 if the number of the incoming heat equal to the amount of work done, and if the heat released is equal to the work imposed on the system. That is, no changes in energy that occur in the system.
Enthalpy (H).
Adala enthalpyh term in thermodynamics that states the amount of internal energy of a thermodynamic system plus the energy used to do work. Enthalpy can not be measured, which can be calculated is the value changes.Mathematically, the enthalpy change can be formulated as follows:ΔH = ΔU + PΔVwhere:
H = enthalpy of the system (joules)
U = internal energy (joules)
P = pressure of the system (Pa)
V = system volume (m3)
Entropy (S)
Thermodynamics (Greek: thermos = 'hot' and dynamic = 'change') is the physics of energy, heat, work, entropy and the spontaneity of processes. Thermodynamics closely related to statistical mechanics where many thermodynamic relations derived.While dealing with a process in which systems exchange matter or energy, classical thermodynamics is not related to the speed of the process, called kinetic. For this reason, use of the term "thermodynamics" usually refers to the thermodynamic equilibrium. In this connection, a key concept in thermodynamics is kuasistatik process, the idealized, the "super slow". Time-dependent thermodynamic processes studied in non-equilibrium thermodynamics.Since thermodynamics is not concerned with the concept of time, it has been proposed that the thermodynamic equilibrium should be called thermostatic.Laws of thermodynamics truth is very common, and these laws are not dependent on the details of the interactions or the systems being studied. This means they can be applied to a system in which a person does not know anything but the balance of energy and matter transfer between them and the environment. Examples include estimates Einstein spontaneous emission in the 20th century and current research on the thermodynamics of black objects.Everyday experience shows that a pond does not freeze in the summer. If a hot object interacts with a cold object, it would not be that hot body is getting hotter and cold items colder, although these processes are not breaking the law of conservation of energy expressed as the first law of thermodynamics.The second law of thermodynamics relates to whether these processes are considered to be the first law abiding principle, occur or do not occur in nature. The second law of thermodynamics as expressed by the Clausius said,? For a cyclical machine it is not possible to produce other effects, in addition to continuously convey heat from an object to another object at a higher temperature. "When viewed Carnot cycle, the cycle consists of four hypotheses irreversible processes: isothermal expansion with the addition of heat, adiabatic expansion, isothermal compression with heat release and adiabatic compression, if the integral of a quantity circling any closed path is zero, then the quantity is the state variable , has a value that is only a characteristic of the state of the system, no matter what the situation is. State variable in this case is the entropy. Gayut entropy change only the initial state and the final state and no gayut process connecting the initial state and the final state of the system.The second law of thermodynamics in the concept of entropy says, "A natural process that began in one state of equilibrium and end up in a state of equilibrium others will move in the direction that causes the entropy of the system and its environment grows".If the entropy associated with the disorder, the statement of the second law of thermodynamics in the natural processes tend to increase equivalent states, and the chaos of the system tends to increase.In the free expansion, the gas molecules occupy the whole space box is more chaotic than when the gas molecules occupy half the space box. If two objects have different temperatures T1 and T2 interact, thereby achieving a uniform temperature T, it can be said that the system becomes more chaotic, in a sense, the statement "all of the molecules in the system corresponds to the temperature T is weaker when compared tostatement of all the molecules in the body corresponds to a temperature T1 and object B corresponds to the temperature T2 ".In the statistical mechanics, the relationship between entropy and chaos parameters are, pers. (1):S = k log wwhere k is the Boltzmann constant, S is the entropy of the system, w is a parameter chaos, the possibility of its being of the system relative to all the circumstances that may be occupied.If the terms change in entropy of an ideal gas in isothermal expansion, where the number of molecules and the temperature has not changed while the volume is greater, then the possibility of a molecule can be found in the area of volume V is proportional to V, ie, the larger V, the greater the opportunity for discovered molecule in V.Possibility of finding a single molecule in V are, pers. (2):W1 = c Vwhere c is a constant. The chances of finding N molecules simultaneously in the volume V is N times the result of w. Namely, the possibility of a state consisting of N molecules in volume V is, pers. (3):w = W1N = (CV) N.If equation (3) substituted into (1), the difference in entropy of an ideal gas in an isothermal expansion process where the temperature and number of molecules does not change, it is worth positive. This means that the entropy of an ideal gas in an isothermal expansion process is increased.Statistical definition of the entropy, ie, equation (1), connect an overview of thermodynamics and statistical mechanics description which allows to put the second law of thermodynamics to statistical base. Direction in which natural processes will occur toward higher entropy is determined by the laws of probability, ie, toward a state more likely. In this case, the state of equilibrium is a state where the maximum entropy in thermodynamics and circumstances are most likely to be statistically. But the fluctuations, ie Brownian motion, can occur around the equilibrium distribution. From this perspective, it is essential that the entropy will increase in every spontaneous process. Entropy can sometimes be reduced. If you wait long enough, the situation is not likely to happen once: the water in the pond suddenly froze on a hot summer day or a local vacuum occurs suddenly in a room. The second law of thermodynamics shows the direction events are most likely, not just possible events.
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