Question

Report Sheet: Post-lab Questions (pay attention to significant figures) 1) 50.00 mL of 0.20 M lead (II) nitrate solution was added to 30 mL of 1.25 M potassium iodide. These compounds react to form a lead (11) iodide, a bright yellow solid. Both solutions were at room temperature at the start of the reaction (19.6 'C). The final temperature of the reaction mixture was 22.2c. a. Write a balanced equation for this reaction. b. What is the theoretical yield of lead (II) iodide? C. What was the mass of water used assuming the density of water was 0.99 g/mL? d. What was the temperature change of the solution? e. What was the solution? f. What was the ? g. What was the enthalpy of this reaction? 2) If 8.00 g of ammonium nitrate is dissolved in 1.0 L of water the temperature drops from 21.00 °C to 20.39 'C. Determine the enthalpy of the reaction:

Answer 1

1) a balanced Equation : pbCNO3),cago + 2 kl caq) → pb 12 (5) + 2 KNOCOD b) moly of Pb(NO3), - 50.00 X020 1000 0.01 mol moly of Kl = 30x1.25/1000 30*1.256.00 = 0.0375 mol Pb CNO3), + 2K17 pblz + 2 KNO3 2 0.01 0.0395 moly of pbl fomed = 0.01 theoretical yeeld of pbly = 0.01% 46! = 4.619 mass of walu = (50 + 30) x 0.99 79.24 temperaten dage= 22-2- 19.6 - 2.600 q solution = mepat - 49.2*4.184 x 2.6 - 862 J qan = -780 = -8627 g) OH = -9/n = 0.862 0.01 = -86.0kJ/mol