ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: physics on February 04, 2010, 08:43:38 pm
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If 0.210g of neon gas occupies hlaf the volume as that occupied by 0.541g of a gaseous hydrocarbon, uner the same conditions of temperature and pressure, then the molar mass of the hydrocarbon is closest to
A. 26gmol^-1
B.52gmol^-1
C.104gmol^-1
D. 138gmol^-1
can some1 plz to show me the working out plz +1 ><
teacher recommened i use this equation
v1=n1
v2=n2
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Use the equations. You can then find the ratio of the volumes to the moles, as you already know that neon occupies half the volume as the gaseous hydrocarbon. This means that twice as many moles of the hydrocarbon are present.
You can then find out the number of moles of neon by dividing the mass present by the molar mass, and double this figure and you'll get the number of moles of the hydrocarbon. As molar mass is mass/n, divide the mass given by n to find the molar mass.
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Use the equations. You can then find the ratio of the volumes to the moles, as you already know that neon occupies half the volume as the gaseous hydrocarbon. This means that twice as many moles of the hydrocarbon are present.
You can then find out the number of moles of neon by dividing the mass present by the molar mass, and double this figure and you'll get the number of moles of the hydrocarbon. As molar mass is mass/n, divide the mass given by n to find the molar mass.
i kinda get it but not really
sorry
=P i'm trying to figure itout
does that mean v1=0.210
and v2=0.420 b/c thats double
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You don't really need to find out the volumes. Rather, you need to interpret the volume ratio as being the same as the number of mol ratio (ie V1/V2 = N1/N2). And as you have the volume ratio already in the question, you can figure out the molar ratio.
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is A.26gmol^-1 the answer