a) In an attempt to determine an accurate value of the gas constant, R, a student heated a container of volume 20.000 dm3 filled with 0.251 32 g of helium gas to 500°C and measured the pressure as 206.402 cm of water in a manometer at 25°C. Calculate the value of R from these data. (The density of water at 25°C is 0.997 07 g cm-3;
(b) The following data have been obtained for oxygen gas at 273.15 K. Calculate the best value of the gas constant R from them and the best value of the molar mass of O2.
|
p/atm
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0.750 000
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0.500 000
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0.250 000
|
|
Vm/(dm3 mol-1)
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29.9649
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44.8090
|
89.6384
|
|
?/(g dm-3)
|
1.07144
|
0.714110
|
0.356975
|