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Molar Volumes Question (1 Viewer)

NichNich

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Hiyas, could anyone please help me out with a little question please?

In Conquering chemistry, it states that:

At 0 degrees and 1.00 atmosphere pressure, the molar volume of all gases is 22.4L and at 25 degrees, and 1.00 atmosphere pressure, the molar volume of all gases is 24.5L.

Yet, other books says that at 25 degrees and 1 atmospheres, the molar volume is 24.8.

Which one should I be using? I understand that the value of 24.8L is the newer value, while the values in conq. chem are older ones. But which ones should I be using for the HSC? Would I get marked down if I used the old ones?

Any help would be great! many thanks in advance!
 

d_elmo

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correct me if im wrong but i think they give you the values on ur sheets with the periodic table and the reduction potentials and all that other info... im pretty sure...
 

Xayma

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24.8 isn't at 1ATM it is at 100KPa, 1.00 atmosphere pressure is 101.3KPa though they now only ask at 100KPa for some stupid dumbing down the course reason.
 

Jezzabelle

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ALWAYS USE THE STANDARDS GIVEN TO YOU IN THE EXAM!!!!!!!!! NO MATTER WAT YOU READ ELSEWHERE, IF THEY SAY H WEIGHS 5.43 YOU USE IT! (even tho everyone knows its 1.008)
 

beta-omega

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don't get other small things like that! In the HSC, they will specifically state at 100kPa and 0C ot 100kPa and 25C. They won't go at 1 atm, that causes confusion.
 

gershy

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Until about a year ago, molar volumes were quoted at 101.3 kPa ( 1 atmosphere) and either 0 or 25 deg celsius. Apparently for years, the standard pressure has been changed to 1 bar which is 100 kPa. The Board of Studies has decided to go with this and since the pressure isa bit lower, the volume is a bit higher. Unfortunately the text books produced in the mad rush to reference the new syllabus were published just before the change took place. Just ignore what's in the textbooks and use the data on the HSC datasheet which you can download.
 

mle9987

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correct me if im wrong

well if im not mistaken they usually give it to you in all exams along with your periodic table! but im pretty sure that its 24.5 and thats the one you should be using
 

Xayma

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No.

You will be using the 100kPa values.
 

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