TrueTears question thread

[lacoste]

I think question one has been answered before.

[TrueTears]

nah it hasn't

[mark_alec]

is a complex ion, so it is correct to treat it as *one* particle, not two (like ).

When you add water, the concentration of all species will decrease. Le Chatelier's principle will never fully oppose a change to the system. Since the concentration decreases, to oppose this change, the system will move in the direction of the most species, namely, towards the left. This will decrease the number of moles of .

[TrueTears]

Oh a complex ion, ahhh now I get it.

Thanks.

[TrueTears]

What is the exact definition/characteristics (and provide an example) of a dehydration reaction and a hydration reaction? More importantly how can you tell if a reaction is a dehydration reaction or hydration reaction?

[mark_alec]

http://en.wikipedia.org/wiki/Hydration_reaction and http://en.wikipedia.org/wiki/Dehydration_reaction

Most of that is beyond what you need to know. A hydration reaction will add water to a chemical, a dehydration reaction will extract water from a chemical.

[TrueTears]

Haemoglobin in blood transports oxygen around the body that keeps the cell alive. Haemoglobin can undergo competing equilibria reactions with oxygen and carbon monoxide that can represented by the chemical equations:

...

...

Carbon monoxide is extremely toxic causing death at concentrations as low as 200 ppm. The values for the 2 equilibrium constants would be such that

A. K1 would be approximately equal to K2
B. K1 would be very much smaller than K2
C. K1 would be very much larger than K2
D. Both K1 and K2 are both very large

[/0]

I think K2 is a lot larger than K1
Carbon monoxide is toxic because it steals haemoglobin from oxygen. Since the concentration of CO is really low and the concentration of O2 is really high, the second reaction will need a really high K2 for CO to react and pose a threat.

[TrueTears]

I don't get the question, is it saying what would be the values of K1 and K2 for CO to pose a threat or for it NOT to pose a threat?

[chem-nerd]

yep K2 is a lot larger than K1, hence B.

CO bonds much more strongly to Hb and forces reaction 1 to move backwards to provide more Hb.

[monokekie]

I don't get the question, is it saying what would be the values of K1 and K2 for CO to pose a threat or for it NOT to pose a threat?

i reckon its asking you to compare the concentration fractions of the two reactions. (TT's minds too great he thinks a lot  )

"Carbon monoxide is extremely toxic causing death at concentrations as low as 200 ppm."
I think the question is hinting the fact that CO undergoes reactions with haemoglobin more readily.

[TrueTears]

Ok, so CO reacts with Hb much more readily, so K2 must be very large because the forward reaction is favoured.

But why does this mean K1 is smaller?

Is it because now there is much much less Hb to react with oxygen so in equation 1 the reaction is favoured backwards so K1 is very small? Is that right interpretation?

[/0]

Ok, so CO reacts with Hb much more readily, so K2 must be very large because the forward reaction is favoured.

But why does this mean K1 is smaller?

K2 must be very large relative to K1, for the reason bolded, so K1 must be smaller.

[TrueTears]

But why does this mean K1 is smaller?

Is it because now there is much much less Hb to react with oxygen so in equation 1 the reaction is favoured backwards so K1 is very small? Is that right interpretation?

That right?

[monokekie]

Ok, so CO reacts with Hb much more readily, so K2 must be very large because the forward reaction is favoured.

But why does this mean K1 is smaller?

Is it because now there is much much less Hb to react with oxygen so in equation 1 the reaction is favoured backwards so K1 is very small? Is that right interpretation?

my interpretation is like this... because the question has stated that they are "competing equilibria reactions" which means less Hb is left for supplying oxyhaemoglobin to da body, as CO stole a lotta Hb to make carboxyhaemoglobins. CO's demand for Hb is sooo large that reaction 1 even has to go backwards to provide more Hb's for the production of oxyhaemoglobins.

( excuse mah poor spelling )