8. a sample of potassium chlorate (kcio,) was heated in a test tube and decomposed 2kc? (s) 302 (g) + 2kcio, (s) the oxygen was collected by the displacement of water at 22'c at a total pressure of 754 torr. the volume of the gas collected was 0.65l and the vapor pressure of water at 22°c is 21 torr. calculate a) the partial pressure of o2 in the gas collected and b) the mass of kcio3 in the sample that was decomposed

Partial pressure of in the gas was 733 torr and mass of in the sample was 2.12 g.

Explanation:

a) Total pressure of gas = (partial pressure of water vapour)+(partial pressure of )

Here partial pressure of water vapour is 21 torr and total pressure of gas is 754 torr.

So, partial pressure of = (total pressure of gas)-(partial pressure of water vapour) = (754 torr) - (21 torr) = 733 torr

b) Lets assume that behaves ideally. Hence-

                                            PV=nRT

where P is pressure of , V is volume of , n is number of moles of , R is gas constant and T is temperature in kelvin

here P = 733 torr = = 0.9646 atm

        V = 0.65 L, R = 0.082 L.atm/(mol.K), T=(273+22)K = 295 K

   So,

                   =

                   = 0.0259 moles

As 3 moles of are produced from 2 moles of therefore 0.0259 moles of are produced from moles or 0.0173 moles of .

Molar mass of = 122.55 g

So mass of in sample =

                                                                    = 2.12 g

its first and third is your answer i did the qustion the fourth isnt right