Answer: Given for oxygen gas volume V=626 cm3=626 mL=0.626 L Pressure P=0.880 at
ID: 699311 • Letter: A
Question
Answer:
Given for oxygen gas volume V=626 cm3=626 mL=0.626 L
Pressure P=0.880 atm and temperature T=133°C=133+273 K
T=406 K.
From Ideal gas equation PV=nRT
Where R=gas constant=0.0821 L atm mol-1 K-1
n=PV/RT=(0.88 atm x 0.626 L)/(0.0821 L atm mol-1 K-1 x 406 K)
n=0.0165 mol.
Given reaction is 2KClO3(s)------->2 KCl(s)+3O2(g)
From the equation the mole ratio between KClO3 and O2 is 2:3, then moles of KClO3=2/3(mol O2)=2/3(0.0165 mol)
Mol KClO3=0.011
Molar mass of KClO3=122.55 g/mol
Mass of KClO3=molesxmolar mass=0.011 molx122.55 g/mol=1.35 g.
The mass of KClO3=1.35 g.