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Homework Statement
Oxgyen gas generated in the thermal decomposition of potassium chlorate is collected over water. At 24 C and an atmospheric pressure of 762 mm Hg ((101.6 kPa), the volume of gas collected is 0.128 L. The vapor pressure of water is 22.4 torr (2.98 kPa). What mass of oxygen is created.
Homework Equations
2KClO3 → 2KCl + 3O2
P1V1 = P2V2
The Attempt at a Solution
I can't explain it mathematically, but I figured that if the water vapour accounted for 2.937 percent of the pressure, it must also account for 2.937 percent of the volume, which leaves 1.242 L of the oxygen gas.
Of course, that could be the problem right there (my assumption) but let's move on for the sake of this post.
The volume of just oxygen gas is 0.1242 L, pressure is 98.61 kPa (found by subtracting pressure of water vapor from total pressure), and the temperature is 298 K. I used those values to find the moles of oxygen produced (0.004963 mol) and mulitplied it by molar mass to get 0.1587 g.
I didn't have enough time to complete this question on my test, but I still want to answer it, particularly because I have an exam in three days (though I doubt there will be any calculation question this difficult --my teacher told me so).
Thanks in advance for all the help! :)