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Wilson Yeh 1L
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Joined: Fri Sep 29, 2017 7:06 am


Postby Wilson Yeh 1L » Wed Mar 07, 2018 6:09 pm

Sulfuryl chloride, SO2Cl2, decomposes by first-order kinetics, and k = 2.81 x 10-3 min-1 at a certain temperature. (a) Determine the half-life for the reaction. (b) Determine the time needed for the concentration of SO2Cl2 to decrease to 10% of its initial concentration. (c) If 14.0 g of SO2Cl2 is sealed in a 2500.-L reaction vessel and heated to the specifi ed temperature, what mass will remain after 1.5 h?

For part C, is the 2500.-L irrelevant? I managed to solve for the final answer without ever taking the volume into account. Am I doing something wrong?

Janine Chan 2K
Posts: 71
Joined: Fri Sep 29, 2017 7:04 am

Re: 15.37C

Postby Janine Chan 2K » Wed Mar 07, 2018 7:54 pm

Nope you're good, if you divide both the initial and final mass by liters to find the concentrations of each, the liters will cancel out when you plug into [A]t=[A]0e-ktanyway.

Sue Xu 2K
Posts: 58
Joined: Fri Sep 29, 2017 7:06 am

Re: 15.37C

Postby Sue Xu 2K » Fri Mar 09, 2018 2:21 pm

It is possible to solve the question without the volume, but you can still calculate the concentration with the mass and the volume first and then calculate the final mass.

Anna Okabe
Posts: 30
Joined: Fri Sep 29, 2017 7:06 am

Re: 15.37C

Postby Anna Okabe » Fri Mar 09, 2018 3:23 pm

I think it would be safer to use the volume and use the molarity every time, so that you can avoid making mistakes in the future.

Emma Miltenberger 2I
Posts: 51
Joined: Thu Jul 27, 2017 3:00 am

Re: 15.37C

Postby Emma Miltenberger 2I » Mon Mar 12, 2018 1:11 pm

In this case, the volume cancels out. However, it is good practice to use the volume to solve for molarity and use molarity in the equation to ensure you do not make an arithmetic mistake on a test.

Michelle Lu 1F
Posts: 50
Joined: Thu Jul 27, 2017 3:01 am
Been upvoted: 1 time

Re: 15.37C

Postby Michelle Lu 1F » Tue Mar 13, 2018 4:58 pm

In this particular situation, the volumes end up cancelling out, so if you were able to recognize this was going to occur, then you could have left it out of the picture. However, common safe practice involves solving for the concentration using the mass given and the volume 2500. L, and this could lead to less errors.

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