Problem 4

4.00 x 10-2 mol of COCl2 (phosgene) is placed in a 1.0 L container and heated to 500K.  At this temperature, 4.5% of the phosgene has dissociated into CO and Cl2.  What is K for the reaction?

COCl2 (g) CO (g) + Cl2 (g)

1. One of the main differences in this problem and the previous ones is the concept of "dissociation".  When a compound is dissociated by a certain percentage, it means that that amount of the original material is gone.  What is 4.5% of 4.00x10-2?

a) 1.80x10-3     b) 0.888    c)  0.180        d) none of these are right

2. In which cell in the IRE table should you enter this dissociated amount of COCl2?

a) I   b) R    c)  E        d) none of these are right

3. What will the sign be on the cell containing the percentage dissociation?

a) + (positive)       b) - (negative)

4. What is the calculated value for K? 

Remember that on the computer, you type numbers in 'E' scientific notation.  For example, 1.234x10-5 is entered as 1.234E-05.

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