Answer:
The correct answers are:
- Krypton: density= 2.8 g/L
- Molar Mass= 63.99 g/mol
- Mass of O₂= 15.29 g
Explanation:
The general equation of an ideal gas is the folllowing:
P x V = n x R x T
Where: P= pressure (in atm), V= volume; n= number of moles, R= gas constant (0,082 L.atm/K.mol) and T= temperature (in K).
For krypton:
P= 671 mmHg = 0,882 atm
V= 478 ml x 1000 ml/1 L= 0,478 L
T= 47ºC= 320 K
MM= 83.8 g/mol (from Periodic Table, Kr is an inert gas so it is a monoatomic gas)
P x V = n x R x T
Since the number of moles of a compound can be calculated by dividing the mass of compound (m) into its molar mass (MM):
n= m/MM
We can replace the expression in the first equation to obtain:
[tex]P x V= \frac{m}{MM} x R x T[/tex]
m/V= [tex]\frac{P x MM}{R x T}[/tex]
Density (d) is equal to the mass per volume (m/V), so we can directly calculate the density:
d= m/V= \frac{P x MM}{R x T}=
= (0.882 atm x 83.8 g/mol)/(0.082 L.atm/K.mol x 320 K)
= 2.81 g/L
For the gas:
d= 2.18 g/L
T= 66ºC= 339 K
P= 720 mmHg= 0.947 atm
d= \frac{P x MM}{R x T}
⇒MM = [tex]\frac{dx R x T}{P}[/tex]
= (2.18 g/L x 0.082 L.atm/K.mol x 339 K)/(0.947 atm)
= 63.99 g/mol ≅ 64 g/mol
For the O₂:
V= 5.60 L
P= 1.75 atm
T= 250 K
MM(O₂) = 2 x Atomic Mass O= 2 x 16 g/mol= 32 g/mol
We can use the second equation:
P x V= \frac{m}{MM} x R x T
⇒ m = [tex]\frac{P x V x MM}{R x T}[/tex]= (1.75 atm x 5.6 L x 32 g/mol)/(0.082 L.atm/K.mol x 250 K)
= 15.29 g≅ 16 g
Answer:
Explanation:
First of all we have to convert our variables to work with equal terms in our ideal gas equation.
PV = nRT
P = pressure = 671mmHg = 0.882atm
Note: (1mmHg = 0.001315atm)
V = volume of the gas = 478cm³
n = no. Of moles =?
T = 47°C = 320K
R = ideal gas constant = 0.08205
cm³atm/mol.k
PV = nRT
n = PV / RT
n = (0.882*478) / (0.08205*320)
n = 16.057 moles
n = mass / molarmass
Molar mass of krypton = 85.798 u
Mass = no. Moles * molar mass
Mass = (16.057 * 85.798) = 1377.66g
Density (ρ) = mass / volume
ρ = m / v = (1377.66 / 478) = 2.88g/cm³
(B) = ρ = 2.18g/L
T = 66°C = 339K
P = 720mmHg = 0.9468atm
R = 0.082 atmcm³/Kmol
density = mass / volume
ρ = m / v ....
v = m/ρ
PV = nRT
n = mass / molarmass
P. (m/ρ) = (m/M) * RT
P / ρ = RT /M
M = (ρ *R*T ) / P
M = (2.18 * 0.082 * 339) / 0.9468
M = 64.00g/mol
(C)
PV = nRT
Mass = ?
V = 5.60 cm³
P = 1.75 atm
T = 250K
Molar mass = 16.0
R = 0.082 cm³atm/Kmol
PV = nRT
n = PV / RT
n = (1.75*5.60) / (0.082*250)
n = 9.8 / 20.5
n = 0.4780 moles
n = mass / molar mass
Mass = no. Of moles * molar mass
Mass = 0.4780 * 16.0
Mass = 7.647g
