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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Texas_Blues on December 17, 2006, 09:00:34 PM

Title: Ideal Gas help
Post by: Texas_Blues on December 17, 2006, 09:00:34 PM
I need help on some Ideal gas problems.


An unknown gas effuses through a small opening in 65.0 minutes while on a equal mass of hydrogen gas goes through the same opening in 9.75 minutes.
Calculate the molar mass.
.... ...
327 ml of 02 is collected over water at 22 Celsius. If the barometric pressure for the day was 752 mm Hg
.
A. What is the water vapor pressure?
b. What is the pressure of the Oxygen gas?
C. How many grams of O2 were collected?
....
A gas effuses through an opening at a rate of one-third as great as the effusion rate of helium.  What is the molar mass of the unknown?
.....
You are given 1.56g KCLO3.  How many mL of Oxygen could theoretically be collected?
A)  at STP
B) at lab conditions of 20 Celsius and 1.1 atm
.....
1g of a gaseous compound occupies .820L at 1atm and 3 Celsius.  Whats the correct formula for the compound?
.....


Thanks this is much appreciated.

And can you show the steps you used to solve these problems.

Thank you
Title: Re: Ideal Gas help
Post by: Texas_Blues on December 17, 2006, 09:15:53 PM
I tried doing these problems and looked all over online to find some way to get an answer but to no luck, I haven't found any.

btw this is for a test study guide.

Thank you
Title: Re: Ideal Gas help
Post by: billnotgatez on December 18, 2006, 12:16:05 AM
http://www.chemicalforums.com/index.php?topic=11859.0
Title: Re: Ideal Gas help
Post by: Yggdrasil on December 18, 2006, 12:41:11 AM
In the future, please follow the Forum Rules (http://www.chemicalforums.com/index.php?page=forumrules) and post your attempts at solving the problems beforehand.  We are willing to help, but only if you have made an honest attempt at solving the problems first.

For some of the problems, it may be useful for you to read up on Graham's law of effusion (http://en.wikipedia.org/wiki/Graham%27s_Law) (link to wikipedia page on Graham's law).
Title: Re: Ideal Gas help
Post by: Texas_Blues on December 18, 2006, 08:14:24 PM
I did attempt to solve some of these I've gotten how to do the first and second one, I cant figure out for the life of me how to do the last one.
And I did read the forum rules.
Title: Re: Ideal Gas help
Post by: Yggdrasil on December 18, 2006, 10:31:18 PM
For the last one, can you think of a way to determine the molecular weight of the gas (grams per mole)?
Title: Re: Ideal Gas help
Post by: Donaldson Tan on December 19, 2006, 03:48:58 AM
Quote from: Texas_Blues on December 17, 2006, 09:00:34 PM
You are given 1.56g KCLO3.  How many mL of Oxygen could theoretically be collected?
A)  at STP
B) at lab conditions of 20 Celsius and 1.1 atm
.....
1g of a gaseous compound occupies .820L at 1atm and 3 Celsius.  Whats the correct formula for the compound?

You would need the chemical equation for the decomposition of KClO3, ie. 2 KClO3 (s)-> 2 KCl (s) + 3 O2 (g)

With this equation, you should be able to solve the last problem on your own.