What are the answers with work to these problems?

Balance this equation co2(g) + h2o (g) show that the balanced equation obeys the law if conversation of mass

Can someone me with questions 12 and 13 plz.

Calculate the ph at the equivalence point for the titration of a solution containing 150.0 mg of ethylamine (c2h5nh2) with 0.1000 m hcl solution. the volume of the solution at the equivalence point is 250.0 ml. kb forethylamine is 4.7 × 10−4 .