When 1.5 m aqueous solutions of sodium carbonate and hydrochloric acid react it produces a carbon dioxide, water and sodium chloride

a. write the balanced chemical equation for the reaction described above (include states of matter)?

Alrighty :) so...

Sodium carbonate is: Na2CO3

Hydrochloric acid is: HCl

This is a double displacement reaction, so the cations and anions are basically going to swap here.

Keep in mind we have the cations: Na(+) and H(+)

And the anions: CO3(-2) and Cl(-)

So we get: Na2CO3 + HCl --> NaCl + H2CO3

Now note that the problem says that our products need to be CO2, H2O, and NaCl.

This might be the tricky part, but it seems like you just have to know that H2CO3 breaks down into H2O + CO2.

H2CO3 --> H2O + CO2

So putting it all together, we get:

Na2CO3 + HCl --> NaCl + H2O + CO2

BUT IS THIS EQUATION BALANCED? We have 2 Na on the left, but 1 Na on the right. We have 1 H on the left, but 2 H on the right...

So after balancing it you should get this:

Na2CO3 + 2HCl --> 2NaCl + H2O + CO2

I'm assuming that you do not need a net ionic equation for this problem and that later on you will use the 1.5M concentrations to solve for some unknown amount.

Lastly, do not forget the states of matter that the problem asks for:

Na2CO3(aq) + 2HCl(aq) --> 2NaCl(aq) + H2O(l) + CO2(g)

Hope this helps, make sure the numbers are the right size! Numbers to the right of an element should be small (subscript) while numbers to the left are normal sized.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.