Question
Question: If 10–4dm3 of water is introduced into a 1.0 dm3 flask at 300 K, how many moles of water are in the ...
If 10–4dm3 of water is introduced into a 1.0 dm3 flask at 300 K, how many moles of water are in the vapour phase when equilibrium is established ?
(Given :Vapour pressure of H2O at 300 K is 3170 Pa ; R= 8.314 J K–1mol–1)
A
5.56 × 10–3mol
B
1.53 × 10–2mol
C
4.46 × 10–2mol
D
1.27 × 10–3mol
Answer
1.27 × 10–3mol
Explanation
Solution
PV = nRT
V = 1 dm3 = 10–3 m3
P = 3170 Pa
R = 8.314 J K–1 mol–1
T = 300 K
3170 × 10–3 = n × 8.314 × 300
n=8.314×3003170×10−3=1.27×10−3mol.