A sample of Ag20 weighing 0. 600 g is heated, causing the silver oxide to decomp
ID: 899406 • Letter: A
Question
A sample of Ag20 weighing 0. 600 g is heated, causing the silver oxide to decompose according to the following equation (balanced): 2Ag20(s) rightarrow 4Ag(s) + 02(g) An inverted test tube filled with water is used to collect 13. 8 mL of oxygen at 27 degree C aud 1 001 bar external pressure. Knowing The partial pressure of water vapor a t27 degree C is 35. 8 mbar calculate The partial pressure of oxygen in the collecting test tube. Calculate the mass of silver oxide in the sample (assume an impure sample). Mass of Ag20: g Calculate the sample purity in percent.Explanation / Answer
a)
1 mol of O2=22.4 L
number of moles of O2 formed = 0.0138/22.4 = 6.161*10^-4 mol
use:
P*V=n*R*T
P*(0.0138L) = 6.161*10^-4 *8.314*10^-2*298
P= 1.11 bar
Answer: 1.11 bar
2)
mol of O2 formed = 6.161*10^-4 mol
2 mol of Ag2O forms 1 mol of O2
So, mol of Ag2O present = 2*6.161*10^-4 mol =1.2322*10^-3 mol
Molar mass of Ag2O= 231.735 g/mol
mass of Ag2O = number of moles * molar mass
= 1.2322*10^-3 * 231.735
=0.286 g
3)
percent purity = 0.286*100/0.600
= 47.6 %
Answer: 47.6 %