Explore BrainMass

# Molecular formula of Nitrogen and Hydrogen molecule

Not what you're looking for? Search our solutions OR ask your own Custom question.

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

A compound contains only nitrogen and hydrogen and is 87.4% nitrogen by mass. A gaseous sample of the compound has a density of 0.977 g/L at 710. torr and 99.9Â°C. What is the molecular formula of the compound?

https://brainmass.com/chemistry/stoichiometry/molecular-formula-nitrogen-hydrogen-molecule-271558

## SOLUTION This solution is FREE courtesy of BrainMass!

Molecular formula of Nitrogen and Hydrogen molecule given pressure, temp, density and percent by mass

A compound contains only nitrogen and hydrogen and is 87.4% nitrogen by mass. A gaseous sample of the compound has a density of 0.977 g/L at 710. torr and 99.9Â°C. What is the molecular formula of the compound?

Solution:
mass of nitrogen=87.4 g
moles of nitrogen=87.4 g Ã— (1 mol)/(14.01 g)
=6.2384 mol

mass of hydrogen=100 g- 87.4 g
=12.6 g
moles of hydrogen=12.6 g Ã— (1 mol)/(1.01 g)
=12.475 mol

(moles of hydrogen)/(moles of nitrogen)=12.475/6.2384
=1.9997
=2

PV=nRT
P/RT=n/V
P/RT=mass/(VÃ—M)
PM/RT=mass/V
PM/RT=d

(710 torr Ã— (1 atm)/(760 torr)Ã—M)/(0.08206 (L atm)/(K mol) Ã—(99.9+273.15)K)=0.977 g/L
(0.9342 atm Ã—M)/(0.08206 (L atm)/(K mol) Ã—373.05 K)=0.977 g/L
M=(0.977 g/L Ã—0.08206 (L atm)/(K mol) Ã—373.05 K)/(0.9342 atm)
=32.01 g/mol
Empirical molar mass = (14.01 + 2 Ã— 1.01) g/mol
= 16.03 g/mol

Ratio = 32.01 / 16.03 = 2

Therefore, the molecular formula is N2H4.

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!