Answer:
The mass of sulphur hexafluoride collected over water is:
MASS IS 115.28g
NUMBER OF MOLE = 0.04 mole.
Explanation:
Gas constant, R = 0.082 L atm/ mol K
Temperature =26° C = 26 + 273 K =>299 K
Pressure = 0.03 atm
Volume = 35 L
Using the ideal gas equation, we can calculate the number of moles and hence the mass from the mass, molar mass, number of mole relationship.
PV = nRT
Re-arrange by making 'n' the subject of the equation:
n = PV / RT
n = 0.03 * 35 / 0.082 * 299
n = 1.05 / 24.518
n = 0.0428
The number of moles is therefore 0.04 moles
Then we calculate the mass:
Number of moles = mass / molar mass
But before we do that, we must calculate the molar mass of the substance collected over water.
The substance is sulphur hexafluoride and has chemical formula SF6 ( S = 32, F = 19)
Molar mass of SF6 = ( 32 + 19*6)
Molar Mass = 146 g/ mol
Equate the values and then solve for the mass, we get:
Mass = number of moles * molar mass
Mass = 0.04 * 146
Mass = 115.28 g
So therefore, the mass of the sulphur hexafluoride is 115.28g and its number of moles is 0.04 mole.
