TopScore Test 1 GChem #56

K

kxb4777

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1. Dental Student

• Jul 23, 2007

• #2

anyone? PUH-PUH-PUH-PUHLEEEEEEEASE!

 

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L

levyusupov

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1. Pre-Dental

• Jul 23, 2007

• #3

post the problem, and i will try to help you.

 

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kxb4777

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• Jul 24, 2007

• #4

When 14.250 moles of PCl5 gas is placed in a 3.00 liter contained and comes to equilibrium at a constant temperature, 40.0% of the PCl5 decomposes according to the equation:

PCl5 (g) <-> PCl3 (g) + Cl2 (g).

What is the value of Kc for this reaction?

 

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doc toothache

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1. Dentist

• Jul 25, 2007

• #5

kxb4777 said:

When 14.250 moles of PCl5 gas is placed in a 3.00 liter contained and comes to equilibrium at a constant temperature, 40.0% of the PCl5 decomposes according to the equation:

PCl5 (g) <-> PCl3 (g) + Cl2 (g).

What is the value of Kc for this reaction?

Click to expand...

At equilibrium the concentrations should be as follows:

PCl5 (14.25-5.7)=8.55moles/3=2.85M
PCl3 (14.25x.40)=5.7moles/3=1.9M
Cl2=PCl3=1.9M

Kc= [1.9] x [1.9]/2.85=1.27

Does this help?

 

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DDS4tehwin

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1. Dentist

• Jul 25, 2007

• #6

doc toothache said:

At equilibrium the concentrations should be as follows:

PCl5 (14.25-5.7)=8.55moles/3=2.85M
PCl3 (14.25x.40)=5.7moles/3=1.9M
Cl2=PCl3=1.9M

Kc= [1.9] x [1.9]/2.85=1.27

Does this help?

Click to expand...

For PCL5, why subtract 5.7 from 14.25? i dun git it

 

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doc toothache

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• Jul 25, 2007

• #7

DDS4tehwin said:

For PCL5, why subtract 5.7 from 14.25? i dun git it

Click to expand...

Because 40% (5.7 moles) of the original 14.25 moles of PCl5 decomposes.

 

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