High School

Calculate the volume of oxygen at NTP obtained by decomposing 12.26 g of [tex]KClO_3[/tex].
(Atomic weights: K = 39.1, Cl = 35.5, O = 16)

Answer :

Answer: 3.61 L

Explanation:


To calculate the moles, we use the equation:


[tex]moles=\frac{\text {given mass}}{\text {Molar mass}}[/tex]


[tex]moles=\frac{12.26g}{122.6g/mol}=0.1moles[/tex]


[tex]2KClO_3\rightarrow 2KCl+3O_2[/tex]


2 moles of [tex]KClO_3[/tex] produce = 3 moles of [tex]O_2[/tex]


0.1 moles of [tex]KClO_3[/tex] produce = [tex]\frac{3}{2}\times 0.1=0.15[/tex] moles of [tex]O_2[/tex]

According to the ideal gas equation:'


[tex]PV=nRT[/tex]


P = Pressure of the gas = 1 atm (NTP)


V= Volume of the gas = ?


T= Temperature of the gas = 20°C = (20+273) K = 293 K (NTP)

R= Value of gas constant in in kilopascals = 0.0821 Latm/K mol


[tex]1\times V=0.15\times 0.0821\times 293[/tex]

[tex]V=3.61L[/tex]

Thus volume of oxygen at NTP obtained by decomposing 12.26 g of [tex]KClO_3[/tex] is 3.61 L