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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: jenny524 on May 19, 2021, 08:25:32 AM

Title: Stoichiometry problems
Post by: jenny524 on May 19, 2021, 08:25:32 AM

Hi,

I have no idea how to solve the first question that deals with the temperature and kPa.
I've only learned STP mole conversions only in class, so this is a new topic for me.
I found that I might need to use the ideal gas law, which I am pretty confident that I failed to use it properly..

Here are the variables that I've found:
n=5/22.4=0.2232142857
R=0.0821
T=303.15
P=98/101.3=0.9674234946

At the end, the result was V=5.74256719L.
Am I supposed to use this volume of carbon dioxide and multiply the conversion factor of 1 mol=22.4L to continue the mole conversions?
(the answer key says it should be 19.5)

For the second one, the equation I set up was:
S+O₂ :rarrow: SO₂

Then 84.6 x 1/32.1 x 1/1 x 6.02x10^23/1= 1.59x10^24 molecules of sulphur dioxide.
However, according to the answer key my teacher gave me says that the answer is 4.01.
Am I incorrect or is it the answer key?

Thank you in advance!!

Title: Re: Stoichiometry problems
Post by: Borek on May 19, 2021, 09:17:22 AM

Use p, V, R and T to find n.