Analytical Chemistry

2 AgNo3 (aq) + Na2S (s) ---------->Ag2S (s) + 2 NaNO3 (aq)

CaCO3 (s) + HCl(aq) --------------> CO2 (g) + CaCl2 (aq) + H2O (l)

If 25.0ml of 0.500M AgNO3 is mixed with 50.0ml of 0.100M Na2S how many grams of Ag2S will form?

What will be the resulting molar concentration of NaNO3 left over in the reaction mixture?

A chemist was presented with a solution of Na2S that had an unknown cncentration.  She carefully added 20.0ml of this solution to a beaker and then added an excess of AgNO3 in order to completely precipitate all of teh sulfide ion present in the Na2S as Ag2S.  After seperating the Ag2S and drying it , she found that the had 0.253g of Ag2S.  What was the molar concentration of the unknown solution?

What mass of CaCO3 would you need to completely neutralize 50ml of 0.1 M HCl?

Suppose a chemist mixed 2.00g of CaCO3 (s) with 100ml of 0.250 M HCl. What mass of each of the three products would form?

In the question above, what is the concentration of CaCl2 in solution after that reaction has been completed?

Please I can do the problem if I understand step-by- step the process of setting it up and solving ....PLEASE HELP  I have to understand this by tomorrow at 2pm!!!