Question

Uranium reacts with fluorine to produce a compound that is a gas at 57 degree celsius

Answer 1

Uranium is reacted with fluorine to form a pure compound. This compound is a gas at 57 °C. At that temperature, and a pressure of 1 atm, it has a density of 13.0 g L-1.  

What is the molecular formula of the compound?

For ideal gas equation,

PV = nRT  

Where, P is pressure

V is volume

N is number of mole

T is temperature

$n = PV/RT$

$n = (1)(1)/(0.0821)(330)$

$n = 0.0369 moles for 1 L$

and weight for 1 L solution is 13.0 g,

$so, molar mass = 13.0 g/0.0369 mole = 352 g/mole.$

Now 238 g /mol is due to the presence of U,

$and 352 – 238 = 114 g /mol for the F,$

$Number of flourine = 114/19 = 6$

so there must be 6 F's  

Molecular formula for compound is UF_6