2. Suppose a piece of metal at 90 °C is quickly transferred into a Styrofoam cup containing 212 grams of water at 24 °C. After a minute or so, the temperature of the contents of the cup is stable at 35 °C. Use 4.2 J/(g.°C) as the specific heat capacity of water and assume that during this time the energy transferred between the contents of the cup and the surroundings is negligible and that there is no heat loss to the cup. (a) How much heat in joules is gained by the water? (b) How much heat in joules is lost by the metal? (c) What is the heat capacity of this piece of metal? (d) If the mass of the metal is 196 grams, what is its specific heat capacity? (e) What is the change of water's entropy? Note the volume of water stays the same. (f) What is the change of total entropy of the system, including both water and metal?

2. Suppose a piece of metal at 90 °C is quickly transferred into a Styrofoam cup containing 212 grams of water at 24 °C. After a minute or so, the temperature of the contents of the cup is stable at 35 °C. Use 4.2 J/(g.°C) as the specific heat capacity of water and assume that during this time the energy transferred between the contents of the cup and the surroundings is negligible and that there is no heat loss to the cup. (a) How much heat in joules is gained by the water? (b) How much heat in joules is lost by the metal? (c) What is the heat capacity of this piece of metal? (d) If the mass of the metal is 196 grams, what is its specific heat capacity? (e) What is the change of water's entropy? Note the volume of water stays the same. (f) What is the change of total entropy of the system, including both water and metal?

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter2: Matter And Energy

Section: Chapter Questions

Problem 29RQ: If 3000 ft3 of air is crossing an evaporator coil and iscooled from 75F to 55F, what would be the...

See similar textbooks

Similar questions

If 3000 ft3 of air is crossing an evaporator coil and iscooled from 75F to 55F, what would be the volume of air, in ft3, exiting the evaporator coil?
A piston-cylinder arrangement contains water at 110°C, 85% quality with a volume of 1 L. What is the initial mass, in grams? The system is heated, causing the 150-mm-diameter piston to rise and encounter a linear spring with k = 800 kN/m. Calculate the specific internal energy (kJ/kg) at this instant knowing that the measured volume is 1.65 L. The heating continues and compresses the spring in the process. When the piston encounters the stops, the pressure is 200 kPa. What is the temperature (in °C) and entropy (in J/K) at this point? Heating continues until the pressure reached 300 kPa. What is the volume, in L at this instant? Illustrate the process in separate P-v and T-v diagram. Note:1000 L = 1m3. Hint: Draw the FBD of the piston in each state.
thermodynamics The heat loss of a human body during sitting still is 400 kJ / h. If the ventilation system of a movie theater with 800 people is broken, after 15 minutes there is no heat loss from the hall walls;a. If the air in the hall is taken as a system, find the increase in the internal energy of the system.b. If the air and people in the room are considered as a system, find the change in the internal energy of the system?
Given the lifting table shown below, The diameter of the plunger DP 20 cm. The ram diameter DR 60 cm , The efficiency is 100 %, The stroke of the plunger is 30 cm. The ram has to raise a load F2 = 20 kN. Find: a) The force F1 exerted on the plunger b) the number of strokes needed to raise the load given above by a distance of 10 cm . c) the volume of oil pumped if the load moves by 30 cm (using plunger force given in a ) d) What will be the new diameter of the ram piston if the new load force is 16 times the force exerted in the plunger the diameter of the plunger is kept to 20cm. (please check the picture carefully).
A body weighs 1000 lbf when exposed to a standard earth gravity g = 32.174 ft/s 2 . ( a ) What is its mass in kg? ( b ) What will the weight of this body be in N if it is exposed to the moon’s standard acceleration g moon =1.62 m/s 2 ? (c) How fast will the body accelerate if a net force of 400 lbf is applied to it on the moon or on the earth?
Calorimetry In a kitchen there are two identical pans that have been previously heated, one of the pans is filled with 1/2 liter of Water at 100◦C and the other with 1/2 liter of oil at 130◦C. After that, no there is more fire that keeps introducing heat to both liquids. In that instant, a person who had cut 300 grams of potato into small cubes at a temperature of 25◦C, decides to pour half the amount of potato in the boiling water and the other half in the burning oil. a) Determine the temperature of the thermal equilibrium between the pore potatoes in the water, and the same for nocao in the oil, considering each cases as isolated systems. (b) Explain why the thermal equilibrium temperatures in both cases are almost the same, mention the physical fundamentals that characterize that result. information in the image respectively: water density: oil density: specific heat of water: specific oil heat: specific heat of the potato:
please help with this question, from thermodynamics A quantity of a certain perfect gas is compressed from an initial state of 0.084 m3, 1 bar to a final state of 0.034 m3, 3.7 bar. The specific heat at constant volume is 0.724 kJ/kg K, and the specific heat at constant pressure is 1.02 kJ/kg K. The observed temperature rise is 139 K. Calculate the increase of internal energy of the gas to two decimal places with the SI unit.
An electric boiler generates 100,000 Btus of heat. Roughly, what is the electrical input of the boiler (in other words, the electrical energy to produce the output), in kilo-watts?
give a specific example of a process that has the energy changes and transfers described. (For example, if the question states “ΔEth > 0, W = 0,” you are to describe a process that has an increase in thermal energy and no transfer of energy by work. You could write “Heating a pan of water on the stove.”) ΔEth < 0, W ≠ 0, Q ≠ 0
Suppose four 30-g ice cubes are added to a glass containing 200 cm3 of orange juice at 20,0°C.You may assume that the orange juice has a density and specific heat capacity the same as water namely: Density = 1,0 g∙cm–3 and specific heat = 4,184 J/gK The heat of fusion (of water) is 333 J/g.Your task is twofold. You must determine:a) Whether or not all the ice will melt; andb) If your finding is that some ice will be left in the juice, you must calculate what mass of ice will be present the moment when thermal equilibrium is reached.
Consider an air conditioning system which requires periodic air renewal. Therefore, fresh air must be introduced by mixing outside air (state 1) and return air from the conditioned room (state 2). The figure shows the principle of operation and data on the air quantities and the evaporator outlet (state 4). Determine the capacity (Q) of the evaporator coil in kJ/kg of dry air.
While the temperature remains constant at 38 degrees C, 2.5 kg of a certain ideal gas whose Cp = 1.1724 kJ/kg-K, Cv = 0.8375 kJ/kg-K rejects 300kJ of heat. If the initial pressure 596kPa, find: (a) the final pressure in kPa 1,887 1,792 1,682 (b) the initial volume in cubic meter 0.46 0.48 0.44 (c) the final volume in cubic meter 0.145 0.155 0.138