- #1
roam
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Homework Statement
A spherical balloon is inflated to a diameter of 36 cm. Assuming that the gas in the balloon is of atmospheric pressure (101.3 kPa) and is at a temperature of 20°C.
(a) How many moles of gas are in the balloon?
(b) If 21% of the molecules in the balloon are oxygen molecules, how many oxygen molecules are in the balloon?
The Attempt at a Solution
(a) I want to use the formula [tex]PV=nRT[/tex]
Volume is [tex]v=\frac{4}{3} \pi (0.18)^2 = 0.1357[/tex]
R is the constant 8.314
So [tex](101.3)(0.1357)=n8.314(20)[/tex]
Now if I solve for n I get [tex]n= {13.74}{166.28} = 0.082[/tex]
This is wrong because the correct answer must be 1.02. Do I need to convert the temprature to Kelvin/absolute temprature? ...because I tried that too & it didn't work.