Posted by Lucy on Sunday, November 4, 2007 at 3:47pm.
PV = nRT
then n = g/molar mass. Post your work if you get stuck.
So far I have: (0.385g)(8.31dm3 times kPa)(200K)(1000cm3)/(7.40 kPa)(mol times K)(200 cm3)(1Dm3) which =639870 g/1480 mol which =432.345 and that is not even close to one of the answers. I don't know where I am going wrong.
I think your units are messed up.
PV = nRT
It's easier to use atmospheres than kPa. R is 0.08205 L*atm/mol*K when atm is used for pressure, P. V must be in liters. I don't know what grams is doing in PV = nRT
P = 750 torr/760 = ?? atm
V = 200 mL = 0.200 L
n = solve for this
R = 0.08205
T in K = 273 + C = 273-73 = 200 K
So
(750/760)atm x 0.200 L = n x 0.08205 L*atm/mol*K x 200 K.
Solve for n, THEN,
n = # mols = grams/molar mass.
You have mols and grams, solve for molar mass. I hope this helps.
Related Questions
chemistry - If 0.385 g of gas occupies a volume of 200 mL at -73 oC and 750 torr...
Chemistry - A quantity of gas weighing 7.10g at 741 torr and 44 degrees C ...
homework college chem. - a sample of gas occupies a volume at 73. 1 mL. As it ...
Chemistry 12 - Gases - A gas is initially at 345 K, 821 torr, and occupies a ...
chemistry - Someone can help me please? A gas sample weighing 0.528 g is ...
chemistry - A sample of gas with a mass of 1.62 g occupies a volume of 941 mL at...
chemistry - a sample of gas occupies 1910ml at -22.8 degrees C and 740 torr. ...
chemistry II - If a 2.15-g sample of gas occupies 750. mL at STP, what is the ...
chemistry II - If a 2.15-g sample of gas occupies 750. mL at STP, what is the ...
chemistry - A gas occupies 10 liters at standard conditions. What volume will ...
For Further Reading
