What is the pressure, in torr, of a gas whose density is 8.0 g/L at a temperature of 25 C above standard temperature and whose molecular weight is 75 g/mol?
Use the gas law and solve for the pressure:
PV=nRT
Where
n=moles of gas
L=volume
R=62.3637 L·Torr/mol·K
and
T=273.15K + 25 C=298.15K
The density of the gas is 8.0g/L and the molecular weight of the gas is 75 g/mol
8.0g//75g/mol= x mol/L
Rearrangement of the gas law gives the following:
P=(n/V)*RT
Plug in x mol/L into the equation and plug and chug.
**Fixed a typo that probably would cause confusion.
Use the gas law and solve for the pressure:
PV=nRT
Where
n=moles of gas
L=volume
R=62.3637 L·Torr/mol·K
and
T=273.15K + 25 C=298.15K
The density of the gas is 8.0g/L and the molecular weight of the gas is 75 g/mol
8.0g/L**/75g/mol= x mol/L
***This leaves mol/L
Rearrangement of the gas law gives the following:
P=(n/V)*RT
Plug in x mol/L into the equation and plug and chug.
To find the pressure of the gas in torr, we can use the Ideal Gas Law equation:
PV = nRT
Where:
P = Pressure (in atm or torr)
V = Volume (in liters)
n = Number of moles
R = Ideal Gas Constant (0.0821 L·atm/(mol·K))
T = Temperature (in Kelvin)
First, we need to convert the given density of the gas to moles per liter:
Density = mass/volume
The mass is given as 8.0 g/L, so we can assume that the given density represents the mass of the gas in one liter.
Next, we need to convert the temperature from Celsius to Kelvin:
T(K) = T(°C) + 273.15
Given that the temperature is 25°C, the temperature in Kelvin would be:
T(K) = 25 + 273.15 = 298.15 K
Now, we can calculate the number of moles using the molecular weight:
n = mass/MW
Given that the molecular weight is 75 g/mol, and the density is 8.0 g/L, we can calculate:
n = (8.0 g/L) / (75 g/mol)
Next, we will convert the number of moles to liters by dividing by Avogadro's number (6.022 x 10^23 mol^-1):
n in liters = (8.0 g/L) / (75 g/mol) / (6.022 x 10^23 mol^-1)
Finally, we can substitute the values into the Ideal Gas Law equation to find the pressure:
P × ([(8.0 g/L) / (75 g/mol)] / (6.022 x 10^23 mol^-1)) × (0.0821 L·atm/(mol·K)) × (298.15 K) = nRT
Solving for P, we get:
P = [(8.0 g/L) / (75 g/mol)] × (0.0821 L·atm/(mol·K)) × (298.15 K) / (6.022 x 10^23 mol^-1)
Calculating this, we can find the pressure in torr.