Answer to Question #179880 in Organic Chemistry for Emma

Question

In the following problems, there are a number of strategies that could be used to solve for x.  Work through each problem until you can decide which strategy to use and explain any assumptions you could make to solve the problem more easily.

iii)  Consider the following            

0.250 moles of CO2 were placed in a 1L closed container at 20000C, 

CO2(g)         ⇌       2CO  +  O2(g)        K=6.40x10-7

iv)    H2 and I2 are placed in a closed container at 4400C, to form HI(g).  If K=49.7, 

4.00 mol of H2(g) and 2.00 mol I2(g) are placed in a 2.00 L container. 

H2(g)    +     I2(g)    ⇌     2HI(g)

Answer 1

The concentrations at the start are:

[H₂] = 1.0 mol/0.50 L = 2.0 mol/L

[I₂] = 1.0 mol/0.50 L = 2.0 mol/L

[HI] = 0 moles therefore 0 mol/L

Fill in the numbers under the reaction for the starting concentrations.

                H₂     +    I₂     <=====> 2 HI

 start   2.0 M     2.0 M                   0 M

Let 'x' be the number of moles of H₂ per litre consumed.

finish   2.0 - x    2.0 - x                     2x