H2 + Br2 equilibrium: finding [HBr] at 700K

[Mathman23]

Hi

I got two questions:

1] A equality reaction:
$\mathrm{2N + O_{2} \rightleftharpoons 2NO}$

a) How does one remove NO from the reaction?


2] An equality mixture $\mathrm{H_2 + Br_2 \rightleftharpoons 2 HBr}$

contains 0,340 mol $H_2$ , 0,220 mol $\mathrm{Br_2}$.

in a canister which has a volume V = 1,0 L.

The mixture is heated to reaches a tempeture of 700K.

Then the reaction has set itself 0,0196 mol is left of $Br_{2}$

a) The concentration of $\mathrm{C_{H_2} = \frac{0,34 mol}{1,0 L} = 0,34 mol/L}$

The concentration of $\mathrm{C_{Br_2} = \frac{0,22 mol}{1,0 L} = 0,22 mol/L}$

b) The equality fraction for the reaction is: $\mathrm{K_c} = \frac{\mathrm{[HBr]^2}}{\mathrm{[H_2] \cdot [Br_2]}}$

c) How do I obtain [HBr] ?

Sincerely

/Fred

 

[chem_tr]

Hello,

An equilibrium may shift either side if the concentration of the contributors can be changed. You may try this by further reacting with O₂ to yield NO₂.

$$NO+\frac {1}{2} O_2 \leftrightharpoons NO_2$$

About your second question, I think you are finding the initial concentrations. This may be incorrect as you seem to omit something. At 700°C, the available hydrogen is completely reacted with oxygen to give water. I don't know any change would be present in HBr and Br₂.

You may find that 0,120 mols of hydrogen is excess in the medium, so it can be converted to water via the reaction $H_2+ \frac {1}{2}O_2 \rightarrow H_2O$. After the equilibrium is reached, you state that 0,0196 moles of bromine is present. You can do the rest from here, if you're stuck somewhere, don't hesitate to ask.

 

[wolfson_1123]

Hi there,

$\mathrm{K_c} = \frac{\mathrm{[HBr]^2}}{\mathrm{[H_2] \cdot [Br_2]}}$

Where i = initial and f = final

[H2init--][Br2init]--[2HBr2init]
[0.340--][0.220 ]--[2---x---]
[H2Fin--]Br2Fin ]--[2HBr2fin]
[0.1396 ][0.0196]--[2---x--]

/_\ = 0.2004

So 2HBr = 2 x /_\ = 2 x 0.2004.

So Concentration = 2/_\ / Volume = 2 x 0.2004 / 1 = well you can do that :-)

And then you can easily calculate the Kc.

Wolfson.