[spinnywheel]

I spend the pass two hours thinking over and over again and  I can't any possible errors in my work, I am beginning to think the work sheet is wrong. 

The W.S. asks you to use the "5 step" method (Bronsted/Lowry's Theory) to figure out the reaction between the equations and explain why your predication matches the evidence.

#1) Solid sodium hydrogen carbonate (NaHCO3) is added to hydrochloric acid (HCl). (evidence: the pH increases and gas bubbles formed)
I dissociated the two compounds and crossed out Na+ and Cl- (both are specs.) and what is left are HCO3-, H3O- and H2O. Strongest acid/base among those 3 are HCO3 as the base and H3O- as the acid so..
H3O + HCO3 <---> H2CO3 + H2O and it favours products.

Just by looking at it (H3O is a very strong acid), there is no way the pH would increase and I don't see a gas in my equation. 

#2) Solid sodium hydrogen carbonate (NaHCO3) us added to sodium hydroxide (NaOH). (pH decreases)
I dissociated the two compounds and crossed out Na+ (x2) and what is let are HCO3M OH and H2O. The strongest acid/base among them is HCO3 and OH. So...
HCO3- + OH- <--> H2O + CO3 and favours products

Again, the pH should not decrease but increase becaue of the OH-.

Can someone tell me if its the just worksheet or is there something with HCO3 that I am not getting?

[rabolisk]

I spend the pass two hours thinking over and over again and  I can't any possible errors in my work, I am beginning to think the work sheet is wrong. 

The W.S. asks you to use the "5 step" method (Bronsted/Lowry's Theory) to figure out the reaction between the equations and explain why your predication matches the evidence.

#1) Solid sodium hydrogen carbonate (NaHCO3) is added to hydrochloric acid (HCl). (evidence: the pH increases and gas bubbles formed)
I dissociated the two compounds and crossed out Na+ and Cl- (both are specs.) and what is left are HCO3-, H3O- and H2O. Strongest acid/base among those 3 are HCO3 as the base and H3O- as the acid so..
H3O + HCO3 <---> H2CO3 + H2O and it favours products.

Just by looking at it (H3O is a very strong acid), there is no way the pH would increase and I don't see a gas in my equation. 

#2) Solid sodium hydrogen carbonate (NaHCO3) us added to sodium hydroxide (NaOH). (pH decreases)
I dissociated the two compounds and crossed out Na+ (x2) and what is let are HCO3M OH and H2O. The strongest acid/base among them is HCO3 and OH. So...
HCO3- + OH- <--> H2O + CO3 and favours products

Again, the pH should not decrease but increase becaue of the OH-.

Can someone tell me if its the just worksheet or is there something with HCO3 that I am not getting?

The worksheet is correct. Nevertheless, I want to know what this 5-step method is. I see why you're not understanding the part about gas bubbles being formed. As far as pH goes, you may have just misunderstood the question, or misunderstood the method.

H3O+ + HCO3- <---> H2CO3 + H2O and it favours products.

The above is correct. First, you wrote H3O- a couple times, but that's probably just a typo. In fact, the equation as you wrote it is the opposite of the dissociation of H2CO3 to H3O+ and HCO3-, and the equilibrium favors H2CO3. So you started out with x amount of H3O+, and most of it has been converted to the products, so the concentration has gone down, which means pH has increased. The misunderstanding may come from the fact that "increased" means increased from a solution of HCl to a solution of H2CO3.

In addition to the acid dissociation, H2CO3 dissociates into H2O + CO2, where CO2 is bubbled out as a gas. This is something that is specific to carbonic acid (H2CO3).

You apply the same reasoning to #2, except there is no gas because H2CO3 is not a product. I hope this helps. If you have additional questions, ask away. It would be helpful if you could post the 5-step method that you learned.