An experiment shows that a 114 mL gas sample has a mass of 0.168 g at a pressure of 697mmHg and a temperature of 30 C.
What is the molar mass of the gas? in g/mol
PV=nRT
You know PV, mass, temp
n= mass/molmass
solve for molmass. Watch units on R
thank you
To find the molar mass of the gas, we can use the ideal gas law equation:
PV = nRT
Where:
P = pressure
V = volume
n = number of moles
R = ideal gas constant
T = temperature
In this case, we are given:
P = 697 mmHg
V = 114 mL (or 0.114 L)
T = 30°C (or 303 K)
We need to convert the pressure from mmHg to atm and the temperature from °C to Kelvin.
1 atm = 760 mmHg
To convert mmHg to atm, divide the pressure by 760:
697 mmHg / 760 mmHg/atm = 0.917 atm
To convert °C to Kelvin, add 273.15 to the temperature:
30°C + 273.15 = 303.15 K
Now we have:
P = 0.917 atm
V = 0.114 L
T = 303.15 K
R = 0.0821 L·atm/(mol·K) (the value of the ideal gas constant)
Now we can rearrange the equation to solve for n (number of moles):
n = (PV) / (RT)
Substituting the given values:
n = (0.917 atm * 0.114 L) / (0.0821 L·atm/(mol·K) * 303.15 K)
Calculating this:
n ≈ 0.0049 moles
Finally, to find the molar mass (M) of the gas, we can use the equation:
M = mass / moles
Substituting the given values:
M = 0.168 g / 0.0049 moles
Calculating this:
M ≈ 34.3 g/mol
So, the molar mass of the gas is approximately 34.3 g/mol.