Thermodynamics - the Doctrine of Energy and Entropy - Assignment Example

1. “Demonstrate an understanding of the first and second laws of thermodynamics and their applications.” The “first law of thermodynamics” is a phrase of the common physical law of the energy perpetuation. The boost in the inner energy of a mechanism is equivalent to the quantity of energy accumulated by heating the system, minus the quantity lost accordingly of the task completed by the system on its environs. (MÜLLER, Ingo, 2007) The second law of thermodynamics is a term that is used to portray the general law of mounting entropy, affirming that the entropy of a secluded system which is not in symmetry will apt to amplify over moment in time, impending a utmost value at symmetry. The appliances of the second law illustrate the reason responsible for transfer of thermal power from the warm object to the cold item. (MÜLLER, Ingo, 2007) 2. Appraise the elementary concepts in combustion: types of combustion, heat of combustion, combustion temperature and chemical equilibrium. Types of combustion – There are six types of combustion, which are as follows: a. Rapid Combustion (MÜLLER, Ingo, 2007) b. Slow Combustion (MÜLLER, Ingo, 2007) c. Complete Combustion (MÜLLER, Ingo, 2007) d. Turbulent Combustion (MÜLLER, Ingo, 2007) e. Microgravity Combustion, and f. Incomplete Combustion (MÜLLER, Ingo, 2007) Heat of combustion – The heat of combustion (ΔHc0) is the power unconfined in the form of heat when one mol of a composite go through absolute combustion in the company of oxygen. The chemical reaction for the same is usually a hydrocarbon’s reaction with oxygen to yield carbon dioxide, water in addition with thermal energy. (MÜLLER, Ingo, 2007) Combustion temperature – Combustion temperature is acknowledged as the heat generated in the incineration compartment in degrees Kelvin. (MÜLLER, Ingo, 2007) Chemical equilibrium - Chemical equilibrium is the condition in which the chemical actions of the reactants and yield enclose no net transform over time. (MÜLLER, Ingo, 2007) 1) Define the four laws of thermodynamics using words, diagrams and equations where appropriate. (8 marks) The laws of thermodynamics are liable to be reasonably uncomplicated to affirm and realize. The laws of thermodynamics facilitate the understanding on how energy is able to be utilized in the world. Thermodynamics comprises of four laws that are undependable on the particulars of the systems under observation or the way they interrelate. (MÜLLER, Ingo, 2007) Therefore, these laws are exceptionally commonly applied to systems in relation to which one is familiar with nonentity other than the equilibrium of energy and substance transfer. These four laws are: A. Zeroth law - A system is acknowledged to be in thermal symmetry when its warmth proves to be stable over time. Let A, B, and C be taken as discrete thermodynamic systems. The zeroth law of thermodynamics is possible to be articulated as: "If A and B are each in thermal equilibrium with C, A is also in thermal equilibrium with B." (MÜLLER, Ingo, 2007) The above verdict declares that thermal equilibrium is a Euclidean relation amid thermodynamic systems. In case it is contributed that all thermodynamic systems are in thermal equilibrium with their own, then thermal equilibrium is also an impulsive relation. Associations that are both reflexive and Euclidean are equivalence relations. (MÜLLER, Ingo, 2007) One outcome of this analysis is that thermal equilibrium is a transitive relation between the temperature T of A, B, and C: B. First law – In accordance with the first law, the energy is indestructible i.e. it is not possible to create or destroy it however; the quantity of energy mislaid in a stable state procedure cannot be bigger than the quantity of energy achieved. It refers to the duo methods that a closed system shifts energy to and from its environs via procedure of heat up or chilling and the course of mechanical work. (MÜLLER, Ingo, 2007) Below given is the equation for Fundamental Thermodynamic Relation: In the above equation, E = internal energy, T = temperature, S = entropy, p = pressure, and V = volume. (MÜLLER, Ingo, 2007) The net transform in inside energy (dE) is equivalent to the thermal energy that flows in “TdS”, subtract the energy that surge out through the arrangement doing task “pdV”. (MÜLLER, Ingo, 2007) C. Second Law - The second law emphasizes on the fact that all energy systems possess a propensity to boost their “entropy" rather than reduce it. (MÜLLER, Ingo, 2007) The modification in internal energy for the functioning substance can be calculated via: D. Third Law - The third law of thermodynamics is a arithmetical law of nature concerning entropy and the unfeasibility of getting complete zero of temperature. The most ordinary accent of third law of thermodynamics is: “As a classification looms towards absolute zero, all course of actions cease and the entropy of the system looms towards a least value” (MÜLLER, Ingo, 2007) 2) “What is entropy? Explain what happens to the motion of water molecules when ice melts into water? What happens to the entropy in this situation?” (2 marks) “Entropy” is function of a extent of heat in a structure which is proficient of doing work. When elevated thermal energy is added to a system at soaring temperature, the boost in entropy is diminutive. When warmth is added to a structure at near to the ground temperature, the augment in entropy is enormous. Consequently, beneath utmost entropy, there is a least of energy accessible for the completion of work and under lowest entropy, there is a greatest amount of energy obtainable for completion of work. (KAYS, William Morrow, 2005) Entropy “S” is defined through an equation linking the variance in entropy of the system to the modification in temperature of the system. For an invariable temperature, the transform in entropy “ΔS” is described by the below given equation: Where, Δq is the quantity of heat captivated in an isothermal and reversible procedure in which the system shifts from single state to another, and T is denoted for the “absolute temperature” (MÜLLER, Ingo, 2007) “Movement of H2O molecules when ice melts into water” Ice is a solid substance possessing a figure sovereign of its storage place. The water molecules in the ice include well-built inter-molecular forces fastening them jointly in a rock-hard, crystallized configuration. These forces hold the molecules collectively disabling the independent move to form Ice. However, the water molecules cannot shift separately; the atoms present in each molecule are capable of shifting to and fort creating a vibration. Due to the vibrations molecules start gaining Kinetic energy. As this energy intensifies, it overcomes the inter-molecule forces and starts the procedure of melting ice to form liquid. (KAYS, William Morrow, 2005) 4) These questions test your understanding of temperature measurements and temperature scales. I) what is absolute zero on the Kelivin, Celsius, Fahrenheit and Rankine scales? “Absolute zero is a precise 0 K on the Kelvin scale, (−) 273.15° on the Celsius scale, °R on the Rankine and (−) 459.67° on the Fahrenheit scale.” (KAYS, William Morrow, 2005) ii) The boiling point of water if 100°C what is this in Kelvins? Boiling point of water in Kelvin is 373.15 K. (KAYS, William Morrow, 2005) 6) Give examples of equilibrium state, steady state and uniform. (3 marks) 7) State whether the following are open or closed systems, give reasons for your answer. i) Rechargeable battery – It is an open system, as alike open systems it permits the passage for mutually energy and substance. (KAYS, William Morrow, 2005) ii) Household refrigerator – It is based on closed system as electrical power is supplied to compressor motor and heat is released in environment. (KAYS, William Morrow, 2005) iii) Radiator – It is an Example of open systems as Hot water go in and chilled water leaves the radiator. (KAYS, William Morrow, 2005) 8) What is the difference between a gas, a liquid and a solid? (2 marks) A gas lacks an explicit figure or volume and comprises of loosely organized molecules while, liquid also lacks explicit shape but unlike gas it comprises a specific volume on the other hand a solid consists of both a specific figure and volume. (MÜLLER, Ingo, 2007) 9) What does thermodynamics tell us with regards to heat transfer? (1 mark) “Heat transfer” is conducted by a number of fundamental principles which are also acknowledged as the laws of thermodynamics defining the ways in which heat transfer relay to task performed by a system and put a number of restrictions on the possibilities for a system to accomplish. (KAYS, William Morrow, 2005) 12) What is Fourier’s Law? What is thermal conductivity? Compare the values of thermal conductivity of metals, insulating materials and gases. What does Fourier"s law have a minus sign? (10 marks) The Fourier's law also acknowledged as law of Heat Conduction expresses that the time tempo of heat transfer through a substance is relative to the depressing gradient in the temperature and to the vicinity at right angles, to that gradient, throughout which the heat flows. (MÜLLER, Ingo, 2007) The Fourier’s Law is further distributed in dual channels i.e. the differential form and the integral form. Differential form The differential formula of Fourier's law states that the basic quantity is confined heat flux. The quantity of energy flows via an infinitesimal orient facade for each unit of point in time. The span of is specified by the quantity of energy flux for each unit of point in time and the course is specified by the vector upright to the surface. (MÜLLER, Ingo, 2007) As a vector equation this show the way to Where (together with the SI units), Is the local heat flux, [W·m−2] Denotes the substance's conductivity, [W·m−1·K−1], Is equivalent to the temperature gradient, [K·m−1]. Integral form Through integrating the “differential form” over the substances entire exterior “S,” the integral form of Fourier's law is attained: (MÜLLER, Ingo, 2007) Where (together with the SI units) = heat transferred per unit of time, The above illustrated differential equation, as soon as integrated for an easy exponential state of affairs, where standardized temperature transversely similarly sized end facades and absolutely protected sides subsist, provides the “heat flow rate” among the end surfaces as: (MÜLLER, Ingo, 2007) Where, A = cross-sectional surface area, ΔT = temperature disparity amid the ends, Δx = space amid the ends. The above stated law formulates of the foundation for the root of the heat equation. “R-value” is the element for heat resistance, the opposite of the conductance. Thermal conductivity is a gauge of the potential of a material to conduct high temperature, dogged by the velocity of heat flow usually all the way through a vicinity in the material divided by the vicinity and by minus the module of the hotness gradient in the course of surge, measured in watts/meter/Kelvin. (MÜLLER, Ingo, 2007) Bibliography KAYS, William Morrow. 2005. Convective heat and mass transfer. McGraw-Hill Professional. MÜLLER, Ingo. 2007. A History of Thermodynamics: The Doctrine of Energy and Entropy. Springer. Read More

These four laws are: A. Zeroth law - A system is acknowledged to be in thermal symmetry when its warmth proves to be stable over time. Let A, B, and C be taken as discrete thermodynamic systems. The zeroth law of thermodynamics is possible to be articulated as: "If A and B are each in thermal equilibrium with C, A is also in thermal equilibrium with B." (MÜLLER, Ingo, 2007) The above verdict declares that thermal equilibrium is a Euclidean relation amid thermodynamic systems. In case it is contributed that all thermodynamic systems are in thermal equilibrium with their own, then thermal equilibrium is also an impulsive relation.

Associations that are both reflexive and Euclidean are equivalence relations. (MÜLLER, Ingo, 2007) One outcome of this analysis is that thermal equilibrium is a transitive relation between the temperature T of A, B, and C: B. First law – In accordance with the first law, the energy is indestructible i.e. it is not possible to create or destroy it however; the quantity of energy mislaid in a stable state procedure cannot be bigger than the quantity of energy achieved. It refers to the duo methods that a closed system shifts energy to and from its environs via procedure of heat up or chilling and the course of mechanical work.

(MÜLLER, Ingo, 2007) Below given is the equation for Fundamental Thermodynamic Relation: In the above equation, E = internal energy, T = temperature, S = entropy, p = pressure, and V = volume. (MÜLLER, Ingo, 2007) The net transform in inside energy (dE) is equivalent to the thermal energy that flows in “TdS”, subtract the energy that surge out through the arrangement doing task “pdV”. (MÜLLER, Ingo, 2007) C. Second Law - The second law emphasizes on the fact that all energy systems possess a propensity to boost their “entropy" rather than reduce it.

(MÜLLER, Ingo, 2007) The modification in internal energy for the functioning substance can be calculated via: D. Third Law - The third law of thermodynamics is a arithmetical law of nature concerning entropy and the unfeasibility of getting complete zero of temperature. The most ordinary accent of third law of thermodynamics is: “As a classification looms towards absolute zero, all course of actions cease and the entropy of the system looms towards a least value” (MÜLLER, Ingo, 2007) 2) “What is entropy?

Explain what happens to the motion of water molecules when ice melts into water? What happens to the entropy in this situation?” (2 marks) “Entropy” is function of a extent of heat in a structure which is proficient of doing work. When elevated thermal energy is added to a system at soaring temperature, the boost in entropy is diminutive. When warmth is added to a structure at near to the ground temperature, the augment in entropy is enormous. Consequently, beneath utmost entropy, there is a least of energy accessible for the completion of work and under lowest entropy, there is a greatest amount of energy obtainable for completion of work.

(KAYS, William Morrow, 2005) Entropy “S” is defined through an equation linking the variance in entropy of the system to the modification in temperature of the system. For an invariable temperature, the transform in entropy “ΔS” is described by the below given equation: Where, Δq is the quantity of heat captivated in an isothermal and reversible procedure in which the system shifts from single state to another, and T is denoted for the “absolute temperature” (MÜLLER, Ingo, 2007) “Movement of H2O molecules when ice melts into water” Ice is a solid substance possessing a figure sovereign of its storage place.

The water molecules in the ice include well-built inter-molecular forces fastening them jointly in a rock-hard, crystallized configuration. These forces hold the molecules collectively disabling the independent move to form Ice. However, the water molecules cannot shift separately; the atoms present in each molecule are capable of shifting to and fort creating a vibration.

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