Question

A block of copper has a mass of 100 kg and an initial temperature of 900 K. Copper can be modeled as an incompressible substance with a specific heat capacity of 0.4 kJ/kg-K.

a.) The copper block is dropped into a large lake at 300 K and allowed to come to thermal equilibrium. How much entropy is generated (kJ/K)?

b.) If a reversible heat engine were connected between the lake and the copper block and operated until the temperature of the copper block reaches the temperature of the lake then how much work (kJ) could be produced?

Answer #1

A cooper block having a mass of 10 kg and at a temperature of
800 K is placed in a well-insulated vessel containing 100 kg of
water initially at 290 K. Calculate:
a) Calculate the entropy change for the block, the water, and
the total process.
b) What is the maximum amount of work that could have been
obtained from the copper block and water in a Carnot engine? The
heat capacities are 4.185 kJ/kg/K for water and 0.398 kJ/kg/K...

A 59-kg iron block and a 20-kg copper block, both initially at
80°C, are dropped into a large lake at 15°C. Thermal equilibrium is
established after a while as a result of heat transfer between the
blocks and the lake water. Assuming the surroundings to be at 20°C,
determine the amount of work that could have been produced if the
entire process were executed in a reversible manner. The specific
heats of iron and copper are 0.45 kJ/kg·K and 0.386...

A 50 kg copper block initially at 350 oC is quenched in a
closed, rigid insulated tank containing 120 L of liquid water at 25
oC. Specific heat of copper, Cc = 385 J/(kgK), specific heat of
liquid water, Cw = 4180J/(kgK). (i) Calculate the entropy change
(kJ/K) of copper block. (ii) Determine the entropy change (kJ/K) of
liquid water.

Two copper blocks, each of mass 1.74 kg, initially have
different temperatures,t1 = 18° C and
t2 = 30° C. The blocks are placed in contact
with each other and come to thermal equilibrium. No heat is lost to
the surroundings.
(a) Find the final temperature of the blocks.
°C
Find the heat transferred between them.
J
(b) Find the entropy change of each block during the time interval
in which the first joule of heat flows.
?S1
= J/K...

A 1.05 kg block of copper at 100°C is placed in an insulated
calorimeter of negligible heat capacity containing 3.50 L of liquid
water at 0.0°C. (a) Find the entropy change of the copper block.
J/K (b) Find the entropy change of the water. J/K (c) Find the
entropy change of the universe. J/K

You have a block of ice at 32 degrees F, and a block of copper
at some other temperature. The blocks have equal mass. Exactly the
same amount of heat is added to each block. This causes the ice to
melt completely, but not to warm up past 32 degrees F. The copper
stays well below its melting point.
How much does the copper expand?
(Express your answer as a percentage, e.g. "the length of the
copper increases by 1%.")...

21. The initial temperature of an iron block of unknown mass is
83 oC. The iron block is cooled by dropping it into an
insulated container that contains 73 Liters of water at 23
oC. After reaching thermal equilibrium, the final
temperature of the iron block and water is measured as 39
oC. If the total entropy change for this
process is 2.5 kJ/oK, determine the mass of the iron in
kg. The specific heat for iron is 0.448 kJ/kg-oK and...

A copper block is removed from a 320 ∘C oven and dropped into
1.20 kg of water at 22.0 ∘C. The water quickly reaches 27.5 ∘C∘and
then remains at that temperature.
What is the mass of the copper block? The specific heats of
copper and water are 385 J/(kg⋅K) and 4190 J/(kg⋅K) respectively.
Express your answer with the appropriate units.

An unknown substance has a mass of 0.125 kg and an initial
temperature of 79.8°C. The substance is then dropped into a
calorimeter made of aluminum containing 0.285 kg of water initially
at 21.0°C. The mass of the aluminum container is 0.150 kg, and the
temperature of the calorimeter increases to a final equilibrium
temperature of 32.0°C. Assuming no thermal energy is transferred to
the environment, calculate the specific heat of the unknown
substance.

An unknown substance has a mass of 0.125 kg and an initial
temperature of 92.5°C. The substance is then dropped into a
calorimeter made of aluminum containing 0.285 kg of water initially
at 27.0°C. The mass of the aluminum container is 0.150 kg, and the
temperature of the calorimeter increases to a final equilibrium
temperature of 32.0°C. Assuming no thermal energy is transferred to
the environment, calculate the specific heat of the unknown
substance.

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