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Anyone help - thermodynamics (urgentish) watch

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1. Hi folks,

Hmm, 13 months since my last visit and my postcount is still 4 posts per day. That pretty much summarises my history here. True to form I'm posting at 2am...

I'm studying mechanical engineering, but badly, and have remedial coursework to complete by Friday. The work is to write a lab report about the performance of a refrigerator. I have this pressure-enthalpy graph of R-12 refrigerant:
/!\CAREFUL, IT'S MASSIVE IMAGE and I can't conveniently resize it.
Spoiler:
Show

I have plotted the refrigerant's cycle on the graph, but I need to determine the specific volume of the refrigerant. I don't have a clue how. I see those lines marked "log10 v = -2" but it's not at all obvious how to use them to find the specific volume...

EDIT: Ahh shoot. It might appear that my plan to 'post graph on TSR, then sit on hands until someone explanes those log(v)=c lines' might have to be replaced with 'search Google again' or even the dreaded 'email tutor for help'...
2. Oh dear...
The lines already on the graph are isochoric. That is each line has a volume associated with it. Since each one is so far in volume from the others they are stated in their log v, which I assume means log (v/1m3kg-1). In short...just read off the graph...

THAT MEANS its OBVIOUS that you want to manipulate "log10 v/1m3kg-1 = -2", to find v.
which means
10^[log10(v/1m3kg-1)] = 10^-2
v/1m3kg-1 = 0.01
v = 0.01m3kg-1

Please learn to use logs and powers in future.
3. (Original post by Mehh)
Oh dear...
The lines already on the graph are isochoric. That is each line has a volume associated with it. Since each one is so far in volume from the others they are stated in their log v, which I assume means log (v/1m3kg-1). In short...just read off the graph...

THAT MEANS its OBVIOUS that you want to manipulate "log10 v/1m3kg-1 = -2", to find v.
which means
10^[log10(v/1m3kg-1)] = 10^-2
v/1m3kg-1 = 0.01
v = 0.01m3kg-1

Please learn to use logs and powers in future.
What, the curved lines marked 'Log10 (v) = -n' are isochoric? Yes, I know what 'isochoric' means, and I can calculate logs, all I need to know is...

...dammit, I've been stupid...

...I needed to know where exactly I needed to find the specific volume. By scribbling on the graph in MSPaint, the answer is clearly Log10(v)=-1.96. Hmm, the last 18 hours have been somewhat wasted. Thanks for the reply.

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