TBR full length 5 #6 answer is not displaying on my computer

[libraryismyhome]

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What is the answer? I put D, but it said wrong and did not display the answer.

The exhaust steam in a one-cylinder steam engine is condensed:


A. to recover the heat energy originally used to vaporize water into steam for evaporating more water in the boiler. B. so that the fluid is more dense and better able to flow through the pump. C. so that the piston does not overheat and expand. D. in order to reduce the pressure in the condenser, to allow vapor to escape from the piston when the exhaust valve is opened

 

[GreenRabbit]

First off I dont have BR, but based on your info...

The answer is A, because condensation releases energy, recycling it instead of discarding it. The other answers don't make sense, eg for D, if there wasn't a good reason to condense the exhaust, then there wouldn't be a condenser in the first place. B is complete nonsense, and for C, the exhaust is already being released, there is no danger to the piston, the question asks why you would choose to do something after it has left the piston.

 

[libraryismyhome]

First off I dont have BR, but based on your info...

The answer is A, because condensation releases energy, recycling it instead of discarding it. The other answers don't make sense, eg for D, if there wasn't a good reason to condense the exhaust, then there wouldn't be a condenser in the first place. B is complete nonsense, and for C, the exhaust is already being released, there is no danger to the piston, the question asks why you would choose to do something after it has left the piston.

wow. a clever logic you got 👍

 

[MedChallenge]

wow. a clever logic you got 👍

BerkeleyReviewTeacher posted what was supposed to show up as the explanation on another thread:

Here is what shows up on my answer key:

6. D is the best answer. The heat released when steam is condensed in the condenser is dissipated through the walls of the system to the external environment and thus is wasted energy. This makes choice A an invalid statement. Both a gas and a liquid are fluids, so both are capable of flowing through the pump. The density of a liquid does not necessarily impact the ease with which it flows. The ease with which it flows depends on its viscosity, which may or may not parallel density. This eliminates choice B. The piston in the cylinder is hot from the steam, so condensing gas in a nearby chamber does not affect the temperature of the piston. The boiling point of water and the condensation temperature of steam are both 100?C, so the chambers adjacent to the piston are at 100?C. The piston is likely going to be at 100?C, so condensing the steam in the condenser does not result in a decrease in the temperature of the piston. Choice C is an invalid statement. When the vapor is condensed into a gas, the pressure in the condenser is reduced. This results in the pressure in the condenser being lower than the pressure in the piston. Because of the pressure differential between the piston chamber and the condenser, steam flows from the piston through the exhaust port and into the condenser (from a region of higher pressure to a region of lower pressure). Flow is made easier, when the exhaust gas is condensed into a liquid once inside of the condenser. The best answer is D.

 

[MrNeuro]

First off I dont have BR, but based on your info...

The answer is A, because condensation releases energy, recycling it instead of discarding it. The other answers don't make sense, eg for D, if there wasn't a good reason to condense the exhaust, then there wouldn't be a condenser in the first place. B is complete nonsense, and for C, the exhaust is already being released, there is no danger to the piston, the question asks why you would choose to do something after it has left the piston.

question regarding this is the cold sink in this setup at the condenser?

if so would this engine become less efficient if the condenser gets hotter w/ time?

would answer choice A be correct if it said

A. to recover the heat energy originally used to vaporize water into steam in order to return entropy back to the universe.?