rhe Ideal Gas Law
SOLUTION:
Density = D = V liter
Weight = if = (n moles) (V
\ mole/
Therefore,
Equation II -3 can be rearranged to give
n _ P
V ~ RT
and thus density of any gas will be given by
RT
Taking the specific gas NH 3 (M = 17.0 g/mole) at the given conditions, we have
(800 torr) ( 17.0 -~]
D= .
} ^
mole/
= 0.641 r
g
( 62 . 4 <2EL^(340 K)
liter
mole K
PROBLEM:
What is the molecular weight of a gas if a 0.0866 g sample in a 60.0 ml bulb has a
pressure of 400 torr at 20°C?
SOLUTION:
Because the number of moles of a substance can always be calculated from its
weight (iv) and mole weight (M) by
W g/mole
Equation 11-3 can be written as
"•
Rearranging and solving for M gives
pT
(0.0866g) (62.4 ^-^) (293 K)
_ wRT _
V
mole K /
= 66 0
PV
(400 torr)(0.060 liter)
' mole
SOLUTION:
Density = D = V liter
Weight = if = (n moles) (V
\ mole/
Therefore,
Equation II -3 can be rearranged to give
n _ P
V ~ RT
and thus density of any gas will be given by
RT
Taking the specific gas NH 3 (M = 17.0 g/mole) at the given conditions, we have
(800 torr) ( 17.0 -~]
D= .
} ^
mole/
= 0.641 r
g
( 62 . 4 <2EL^(340 K)
liter
mole K
PROBLEM:
What is the molecular weight of a gas if a 0.0866 g sample in a 60.0 ml bulb has a
pressure of 400 torr at 20°C?
SOLUTION:
Because the number of moles of a substance can always be calculated from its
weight (iv) and mole weight (M) by
W g/mole
Equation 11-3 can be written as
"•
Rearranging and solving for M gives
pT
(0.0866g) (62.4 ^-^) (293 K)
_ wRT _
V
mole K /
= 66 0
PV
(400 torr)(0.060 liter)
' mole