...Heat of Fusion of Water 4-1: Heat of Fusion of Water The molar heat of fusion for a substance, ∆Hfus, is the heat required to transform one mole of the substance from the solid phase into the liquid phase. In this assignment, you will use a simple coffee cup calorimeter and a thermometer to measure the molar heat of fusion for water. 1. Start Virtual ChemLab, select Colligative Properties, and then select Heat of Fusion of Water from the list of assignments. The lab will open in the Calorimetry laboratory with a beaker of ice on the balance and a coffee cup calorimeter on the lab bench. 2. Click on the Lab Book to open it. Record the mass of the ice on the balance in the data table. If the mass is too small to read, click on the Balance area to zoom in. Note that the balance has already been tared for the mass of the empty beaker. 3. 100 mL of water is already in the coffee cup. Use the density of water at 25 C (0.998 g/mL) to determine the mass of water from the volume. Record the mass in the data table. Make certain the stirrer is On (you should be able to see the shaft rotating). In the thermometer window, click Save to begin recording data to the lab book. Allow 20-30 seconds to obtain a baseline temperature of the water. 4. Drag the beaker from the balance area until it snaps into place above the coffee cup and then pour the ice into the calorimeter. Click the thermometer and graph windows...
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...Running head: Study Of Heat Heat and Temperature Marcus A. Bullock SCI 110 Intro to Physical Science The Study Of Heat and Temperature Heat is a function of the velocity of all the molecules of a substance. Kinetic theory and heat transfer are both in motion, in Kinetic theory all states of matter are in vigorous motion and heat transfer is associated with the motion of atoms or molecules. The kinetic theory of matter says that all matter is made of particles that are in constant motion. Matter is made of constantly moving particles, which tells us how the matter in solids, liquids, and gases behaves. The reason heat relates to the kinetic theory is because, gases consist of great numbers of molecules moving in all directions, that their impact on a surface causes the gas pressure to rise. Heat study is explained through the movement of warmer and cooler objects, the changing of temperature. It is not a theory of sorts like kinetic theory of matter is. Scientist state that heat is defined as “something” that moves between objects when two objects of different temperatures are brought together. The more heat that is produced the higher the kinetic energy level of an object or substance it has. Temperature on the other hand, can be defined as the degree of hotness or coldness of an object. Temperature is the measure of the average heat or thermal energy of particles in a substance. The relationship between heat and temperature is described...
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...HEAT 4.1 UNDERSTANDING THERMAL EQUILIBRIUM 1. Define: The measure of the degree of hotness of an object. (a) Temperature Measured in SI unit Kelvin, K A hot object is at a higher temperature than a cold object. Form of energy, measured in Joules, J (b) Heat Heat is transferred from hotter object (higher temperature) to colder object (lower temperature) When an object is heated, it will absorb heat energy and the temperature will increase. When an object is cooled, it will release heat energy and the temperature will decrease. (c) Thermal Two objects are in thermal contact when heat energy contact can be transferred between them. (d)Heat transfer When two objects with different degrees of hotness come into thermal contact, heat energy is transferred between the two objects. (e) Mechanism of Thermal Equilibrium Energy is transferred at a faster rate from the hotter object to the colder object. Energy is also transferred from the colder object to the hotter one, but at a slower rate. There is a net flow of energy from the hotter object to the colder object. (f) Thermal When two objects are in thermal equilibrium, there is Equilibrium no net flow of heat between them. Two objects in thermal equilibrium have the same temperature 60 The hotter object cools down while the colder object warms up . After some time, energy is transferred at the same rate between the two objects. There is no net heat transfer between the objects. The two objects are said to be in thermal equilibrium...
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...Intro to Physical Science Assignment # 2 Johnnie Currie JR. November 8, 2011 Strayer University 1. How does the study of heat relate to the kinetic theory of matter? Theory for ideal gases makes the following assumptions the gas consists of very small particles, all no zero mass. The number of molecules is large such that statistical treatment can be applied. These molecules are in constant, random motion. The rapidly moving particles constantly collide with the walls of the container. 2. What is heat? Heat is energy that is transferred from one body, region or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. 3. What is temperature? Temperature is a physical property of matter that quantitatively expresses those common notions of hot and cold. Object of low temperature are cold, while various degrees of higher temperature are referred to as warm or hot. 4. What is the relationship between heat and temperature? The relationship between heat and temperature is heat is a form of energy that exists on its own that is manifested of the total energy moving from one substance to another. Temperature is a material property it is a measurement of the average kinetic energy of molecules vibrating in a substance. 5. How are they different? The difference is heat is a thermal energy transferred from one object to another because of a temperature difference, and temperature is a relative measure...
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...Introduction to Heat and Temperature Gonzalo Leon Strayer University 2012/01/27 Introduction to Heat and Temperature Relation between the Study of Heat and Kinetic Theory Kinetic theory can be describes as a scientific theory of the movement of an object. Kinetic theory relates to capacity of a subject to do work on another object due to their motion. Kinetic theory of matter explains that the same is compose of tiny pieces of, atoms or molecules in continues motion. The theory states that the actions of matter inside an object and the actions heat generates. Kinetic theory explains as well the temperature transition by the means of transmission, where thermal powers shows to be conducted throughout matter, heating up cooler regions. This reaction is the delivery of heat or heat flow. Kinetic theory relates to the study of heat due to the fact that once heat is produced, kinetic energy is created as well. Heat energy can convert or transfer its self into kinetic energy that could make a subject move. Definition of Heat and Temperature Heat: Heat could simply be summarize as been energy. It is the delivery of Kinetic energy from one subject to a different one. Heat is conveyed in three different ways: radiation, convection and conduction. An example of heat by radiation could be infrared energy when this one strikes a surface. Heat by conduction occurs when two subjects are in direct contract with one another. Heat by convection can occur as the movement of a liquid...
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...Heat relates to the gases that consist of great numbers of molecules moving in all directions. When they impact on the surface they cause the gas pressure to move, this is what we feel as heat it is basically kinetic energy of motion. Heat is made up of massive numbers of small particles of single atoms or molecules in continuous motion. It’s the behavior of matter in an object and the movement that heat produces. It’s also the connection between pressure, temperature and volume properties of gas. Heat is energy. It moves in waves like other forms of energy, and can change the matter it touches, by heating up which starts molecules moving. It is what happens to matter that is in motion. The atoms and molecules move back and forth hitting each other causing a form of energy that is in all matter. Heat is a measure of the total inner energy that has been absorbed or transferred from one body to another. Heat is a form of energy that is measured by temperature. Although heat and temperature are used interchangeably, heat and temperature are not equal. Heat is used in chemical reactions to give energy to reactants. Chemical reactions lose energy to the system in the form of heat, which is described as entropy in the Laws of Thermodynamics. If there are any changes in it create changes in temperature Temperature is the degree how hot or cold something is. It is not energy, it is something that could be measured, it also refers to how fast the molecules and atoms are moving a...
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...The most important concept to understand within the fire phenomena is heat transfer. Heat transfer is everywhere within the aspects of fire, such as fire development. Before the three types of heat transfer can be explained, a few more things need to be understood. Such as heat is the transfer of energy based on a temperature difference between two objects. Also that temperature is a measure of kinetic energy of the molecules in an object. Now the three types of heat transfer and first up is Conduction which is the transfer of energy in the form of heat by direct contact through excitement of molecules with driven by a temperature difference. Energy travels from a high to a low and the same thing happens with heat. When the high temperature molecules collide with the low temperature molecules, a transfer of energy occurs from the hot, more energetic molecules to the colder, less energetic molecules and this is recognized as conduction. Conduction is most prevalent in solids but it can also be found in liquids and gases. The rate at which heat is transmitted through a material by conduction depends on thermal conductivity which is a characteristic of a material and its mass. The easiest way to think of conduction is to hold a metal rod by one end and put the other over a fire. Eventually the hot energetic molecules from the fire will transfer to the cold, less energetic molecules of the metal rod and slowly creep up the rod to the cold end where it is being held and...
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...The most important concept to understand within the fire phenomena is heat transfer. Heat transfer is everywhere within the aspects of fire, such as fire development. Before the three types of heat transfer can be explained, a few more things need to be understood. Such as heat is the transfer of energy based on a temperature difference between two objects. Also that temperature is a measure of kinetic energy of the molecules in an object. Now the three types of heat transfer and first up is Conduction which is the transfer of energy in the form of heat by direct contact through excitement of molecules with driven by a temperature difference. Energy travels from a high to a low and the same thing happens with heat. When the high temperature molecules collide with the low temperature molecules, a transfer of energy occurs from the hot, more energetic molecules to the colder, less energetic molecules and this is recognized as conduction. Conduction is most prevalent in solids but it can also be found in liquids and gases. The rate at which heat is transmitted through a material by conduction depends on thermal conductivity which is a characteristic of a material and its mass. The easiest way to think of conduction is to hold a metal rod by one end and put the other over a fire. Eventually the hot energetic molecules from the fire will transfer to the cold, less energetic molecules of the metal rod and slowly creep up the rod to the cold end where it is being held and then...
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...NAVY ENGINEERING COLLEGE HEAT & MASS TRANSFER LAB MANUAL ENGINEERING SCIENCES DEPARTMENT HEAT & MASS TRANSFER LAB MANUAL ENGINEERING SCIENCES DEPARTMENT LAB INSTRUCTIONS 1. No late submissions 2. If you miss the submission time, you will be marked zero in that lab 3. If cheating or plagiarism is observed in the lab report, zero will be marked in that lab. 4. Detailed calculations should be shown. 5. Neat work will earn good marks. 6. Graphs should be made by hands. MS excel graphs will not be accepted. LAB MARKS DISTRIBUTION LAB REPORT/ ATTENDENCE | 50% | LAB PERFORMANCE | 10% | MID TERM ASSESMENT/QUIZES | 10% | FINAL LAB ASSESMENT | 30 % | TOTAL | 100% | TABLE OF CONTENTS S.NO | DATE | OBJECTIVE | PAGE NO | SIGNATURE | 1. | | To show that the intensity of radiation on a surface is inversely proportional to the square of the distance of the surface from the source of radiation | | | 2. | | To show the intensity of radiation various as fourth power of source. | | | 3. | | Determination of barrier temperature gradient between two different metals in end to end pressure contact. | | | 4. | | To perform energy balance on air flowing throw a duct heated by cylindrical rod | | | 5. | | To perform energy balance on air flowing throw a duct heated by cylindrical rod using DAQ | | | 6. | | Determination of a mean surface heat transfer coefficient for tubes...
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...HEAT TRANSFER Essay 1 Heat is one of many forms of energy that can be transformed into each other in accordance with the First Law of Thermodynamics. However, it is important to note that the energy contained within any substance cannot be regarded as heat. In fact, heat only exists when it is transferred between two media and then only due to a temperature difference between those media. There are many misuses of the word “heat”. It is not uncommon to describe the temperature in an oven as being 350 degrees of heat. Also, the energy contained in a medium is sometimes said to be the heat contained within that medium. These uses, as well as other misuses, are excluded by the definition: heat is energy in transit due to a temperature difference. Heat transfer is one of the most ubiquitous processes in nature. It is also commonly encountered in virtually all devices, machines, instruments, and living creatures. With such a broad range of application, heat transfer becomes a key part of the engineering knowledge base. Like most undergraduate subjects, the subject matter taught in heat transfer courses represents the academic view of the topic. That view is highly sanitized and drastically simplified compared with reality. The homework problems in the typical undergraduate course are also contrived to be solvable by use of the knowledge base that is conveyed in standard textbooks and in the classroom. Expertise in solving such problems is misleading because those problems...
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...Chemistry Lab Chemistry Lab Aim: To investigate the specific heat capacity of water, copper and aluminium by using a caloriometer. Results: 1. Ohms Law: I=v/r, equation 3 = E=vlt hence you get E= v2t/r when ohms law is applied to equation 3. 2. De ionized water is used as it is the purest form of water, as it doesn’t contain ions from the soil like normal water which allow the conduction of electricity as normal water allows electrons to flow, thus preventing any extraneous variables to affect the experiment. 3. The value for Tf = 100o as water has a boiling point of 100o 4. SH = 1.00cal.g-1.c-1 m= density x volume (Tf – Ti) = 100 – 19.9 = 1 x 1,000ml = 80.1 = 1,000g EH2O = SH.m.(Tf – Ti) = 1 x 1,000 x 80.1 = 80,100cal Converting to Joules (1cal = 4.184j) 1000*4.184* 80.1= 335,138.4 joules g-1 deg-1 EKettle= V2.t / R V= 240 t= 219s R= 34.7 2402 * 219/34.7 =363,527.38 joules = E of kettle 5. The amount calories required to raise 1 gram of water by 1 degree Celsius is specific heat. Hence 80,100 calories are required to heat up the water, this shows the association between question 4. 6. In question 4, it can be observed that the energy produced by the kettle was 363,527.38 joules, however only = 335,138.4 joules g-1 deg-1 of energy was required to raise the water 80.1 degrees Celsius. Thus...
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...of the secondary fluid to the heat exchanger may change with time. This means that in order to maintain a consistent secondary fluid outlet temperature, the heat supplied to the heat exchanger must also vary. This can be achieved by using a control valve on the inlet to the primary side of the heat exchanger, as shown in Figure 13.2.1. Fig. 13.2.1 Typical temperature control of a steam/water shell and tube heat exchanger A control valve is used to vary the flowrate and pressure of the steam so that the heat input to the heat exchanger can be controlled. Modulating the position of the control valve then controls the outlet temperature of the secondary fluid. A sensor on the secondary fluid outlet monitors its temperature, and provides a signal for the controller. The controller compares the actual temperature with the set temperature and, as a result, signals the actuator to adjust the position of the control valve. For a constant heating area and heat transfer coefficient, the rate at which heat is transferred from the steam to the secondary fluid for a particular heat exchanger is determined by the mean temperature difference between the two fluids. A larger difference in mean temperatures will create a large heat transfer rate and vice versa. On partially closing the control valve, the steam pressure and the temperature difference fall. Conversely, if the control valve is opened so that the steam mass flow and hence pressure in the heat exchanger rise, the mean temperature...
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...The refrigerant that is typically used in an absorption chiller is distilled water and the absorbent is lithium bromide. These two fluids, the refrigerant An introduction to the absorption refrigeration cycle Absorption cycle versus vapour-compression cycle There are two fundamental differences between the absorption refrigeration cycle and the vapour-compression refrigeration cycle with which we are more familiar. The first difference is that the compressor is replaced by an absorber, a pump and a generator. The second is that, in addition to the refrigerant, the absorption refrigeration cycle uses a secondary fluid, called the absorbent. The condenser, expansion device, and evaporator sections, however, are the same. Refrigerant solutions and the absorbent, are mixed inside the chiller in various concentrations. The term dilute solution refers to a mixture that has a relatively high refrigerant content and low absorbent content. A concentrated solution has a relatively low refrigerant content and high absorbent content. An intermediate solution is a mixture of dilute and concentrated solutions. The absorption refrigeration cycle The four basic components of the absorption refrigeration cycle are the generator and condenser on the high-pressure side, and the evaporator and absorber on the low-pressure side. The pressure on the high-pressure side of the system is approximately ten times greater than that on the low-pressure side. [pic] Starting on...
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...trODuct ION tO G rO u N D S O u rc e Heat P uMP SyS teM S chris arkins This note TEC 6, originally published in February 1999, was reviewed by Chris Arkins in January 2004. This summary page includes recent updates to the topic since publication. SUMMARY OF actIONS tOwarDS SuStaINable OutcOMeS Introduction Alternative low energy air conditioning solutions are now commonly sought in preference to typical air conditioning systems for both residential and commercial applications. The industry has seen a growing emergence of ground source heat pump (GSHP) installations throughout Australia over the last five years. A broad spectrum of facilities ranging from domestic housing, hospitals, education facilities, commercial offices and civic buildings to name a few, are now realising the environmental benefits offered by GSHP systems over more commonly used air conditioning systems. This summary note provides a brief overview of the previous note and provides an update on changes that have occurred since. basic Strategies Heat rejection is fundamental to all air conditioning systems. Typically, unsightly roof mounted air cooled condensers and cooling towers are by far the most commonly used method for rejecting heat from a building. Ground source heat pumps are somewhat different to the norm. Basically GSHP are refrigeration machines that provide heating and cooling by using ground water and the earth as a medium to reject and/or absorb heat and as such do not require air cooled...
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...HEAT TRANSFER Modes of Transferring Heat Heat is always transferred when a temperature difference exists between two bodies. There are three basic modes of heat transfer: Conduction involves the transfer of heat by the interactions of atoms or molecules of a material through which the heat is being transferred. Convection involves the transfer of heat by the mixing and motion of macroscopic portions of a fluid. Radiation or radiant heat transfer, involves the transfer of heat by electromagnetic radiation that arises due to the temperature of a body. CONDUCTION Conductive Heat transfer takes place as conduction if there is a temperature gradient in a solid or fluid Conduction will take place if there exist a temperature gradient in a solid (or stationary fluid) medium. Energy is transferred from more energetic to less energetic molecules when neighboring molecules collide. Conductive heat flow occurs in direction of the decreasing temperature since higher temperatures are associated with higher molecular energy. Fourier's Law expressed conductive heat transfer as: q = k A dT / s Where q = heat transfer (W, J/s, Btu/s)A = heat transfer area (m2 , ft2)k =thermal conductivity of the material(W/m.K or W/m℃, Btu/(hroF ft2/ft))dT = temperature difference across the material (K oroC,oF)s = materialism thickness (m, ft) Example of Heat Transfer by Conduction is A plane wall constructed of solid iron with thermal conductivity 70 W/m℃, thickness 50 mm...
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