2.41g of a gaseous compound containing only boron and hydrogen was transferred to a previously evacuated 2.22L flask. After the transfer the pressure in the flask was measured to be 0.96atm at temperature 298K. What is the molecular formula of the compound?
The answer is B2H6 but i dont know how to get it i tried everything and cant figure it out.
Plz give a detailed explanation as to how you are solving it.
The answer is B2H6 but i dont know how to get it i tried everything and cant figure it out.
Plz give a detailed explanation as to how you are solving it.
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1. Use the ideal gas law to calculate moles of gas in the flask:
PV = n RT
(0.96 atm) 2.22 L = n (0.0821 Latm/molK) ( 298 K)
n = 0.0871 moles gas
Now, you can calculate the molar mass: 2.41 g / 0.0871 mol = 27.7 g/mol
Since the molar mass of B is 10.8, and the molar mass of H is 1, 1 B would be too low, and 3 B would be to big, so try B2. That would have a mass of 21.6, which leaves 6 H So, B2H6 works.
PV = n RT
(0.96 atm) 2.22 L = n (0.0821 Latm/molK) ( 298 K)
n = 0.0871 moles gas
Now, you can calculate the molar mass: 2.41 g / 0.0871 mol = 27.7 g/mol
Since the molar mass of B is 10.8, and the molar mass of H is 1, 1 B would be too low, and 3 B would be to big, so try B2. That would have a mass of 21.6, which leaves 6 H So, B2H6 works.