please answer these questions

49. You are planning a lecture demonstration to illustrate an endothermic process. You want to lower the temperature of 1400. 9 of water in an insulated container from 25.0C to 10.0C. What mass of NH4Cl(s) should you dissolve in water to achieve this result? The heat of solution of NH4Cl is 14.8kJ/mol. (Value: 4) 50. a) The barium ion, Ba2., is toxic within the human body. In spite of this, barium sulfate (BoSO4) is given to patients to drink before they have x-rays of their digestive tract. Why is it safe to ingest BaSO4 ? (Value: 2) BaSO4(s)4Ba2(aq)+SO2(q) b) Calculate the molarity of a solution containing 25.0g of sodium phosphate, Na3PO4, in 500.mL of solution. (Value: 2) 51. The decomposition of ammonia to nitrogen and hydrogen results in the following equilibrium. NH3(g)411N2(g)+H2(g)H=46.1kJ The activation energy for the forward reaction is 335kJ/molNH, without a catalyst and 197kJ/mol with an osmium catalyst. a) Sketch an activation energy diagram to represent this equilibrium. Label activation energy and enthalpy on the diagram. Show the reaction paths for both the catalyzed and noncatalyzed reaction. (Value: 3) b) Using collision theory, explain why the asmium catalyst increases the rate of the reaction. (Value: 1) (Value: 2)