NaCl NH_3 NaCH_3CO_2 HCl NH_4Cl CH_3CO_2H NaOH NH_4CH_3CO_2 use a stir rod or di
ID: 993831 • Letter: N
Question
NaCl NH_3 NaCH_3CO_2 HCl NH_4Cl CH_3CO_2H NaOH NH_4CH_3CO_2 use a stir rod or dispoasable pipet to dab solution from the bottle onto the pH strip. Do not dip the strip into a beaker or into the stock bottle. Record the pH values Dispose of pH strips into the trash - not in the waste container Measure the pH of prepared 0.010 M solution of the following substance. Use a small, clean container so that you do not need more than 10 ml of each NaCl NH_3 NaCH_3CO_2 HCl NH_4Cl CH_3CO_2H NaOH NH_4CH_3CO_2 Measure the pH of common household solution. Record your results Measure the pH of three of the unknown solution. Determine the identify of these solutions from the following possibilities. The Ka of HCH_3CH_2CO_2 is 1.3 Times 10^-5 1.0 Times 10^-3 M HCH_3CO_2 1. Times 10^-4 M HCl 0.25 M NH_4Cl 1.0 Times 10^-4 M HCH_3CH_2CO_2 Determine the Effectiveness of Antacids Use the procedure that you wrote for the pre-lab exercise that was approved by your instructor to measure and compare the effectiveness of two different antacids. In Part B, you measure^the pH of 0.010 M solutions of ammonia (NH_3) and acetic acid (CH_3CO_2H) and you also measured the pH of household ammonia and vinegar. Based on your pH measurements, which solution is a higher concentration? Rank the four solutions in terms of increasing concentration. Explain your answer. In Part B, you measured the pH of unknown solutions. Explain the identity of those solutions based on your pH data. Vinegar is a 5% solution of acetic acid in water. Calculate the theoretical pH of this solution and compare the pH to your results. Based on the pH value you measured for household ammonia, calculate the initial concentration of ammonia in molarity. The K_b of NH_3 is 1.8 times 10^-5. Discuss and explain your results to Part C.Explanation / Answer
For question 2, all you have to do is match the pH values to the standard solutions of previous part, then, you will know the identity of them.
For question 4, here's what you have to do. With the pH given, we can calculate the OH- and then, use the equilibrium equation:
NH3 + H2O ---------> NH4+ + OH- Kb = 1.8x10-5
Now I need the pH you measured in your household solution. As you are not giving this data, I'll use the data for part 2 of the procedure. The pOH and OH for this solution is:
pOH = 14-10.26 = 3.74
[OH] = 10-3.74 = 1.82x10-4 M
This is the equilibrium OH so the innitial concentration would be:
r: NH3 + H2O ---------> NH4+ + OH- Kb = 1.8x10-5
i: Y 0 0
e: Y-1.82x10-4 1.82x10-4
1.8x10-5 = (1.82x10-4)2 / Y-1.82x10-4
1.8x10-5(Y - 1.82x10-4) = 3.3124x10-8
1.8x10-5Y - 3.28x10-9 = 3.3124x10-8
Y = 3.2124x10-8 + 3.28x10-9 / 1.8x10-5
Y = 1.97x10-3 M
Hope this helps
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