Question

1. Calculate the hydrogen ion concentration, [H⁺ ], for the two weak acids (pH=-log[H⁺ ], or [H⁺ ]=antilog (-pH). If you have difficulty finding or using the antilog function on your calculator, simply use this: [H⁺ ]=10^-pH .

2. Calculate the hydroxide ion concentration, [OH^- ], for the weak base using this formula: pOH=14-pH, then [OH^- ]=antilog (-pOH) or [OH^-]=10^-pOH.

3. Calculate the molar concentrations of the vinegar as well as ammonia. Both are industry standard 5.00% by mass solutions in water. This means 5.00 g of solute/ 100.00 g of solution. Assume that the solution is mostly water (which it is) and thus has a density of 1.00 g H₂O/1.00 ml H₂O. Now use this information plus the molar masses of the vinegar (acetic acid) and ammonia (ammonium hydroxide) to change the 5.00 g solute/100.00 g solution to M, which is mol solute/L solution (H₂O). Record these concentrations in your data table.

4. Calculate the K_a or K_b using the formula given in the introduction.

5.Calculate the pK_a or pK_b (pK_a/b =-log K_a/b)

Reagents	pH level
Table Salt (NaCl)	7.33
Washing Soda (Na2CO3)	10.89
Smelling Salts ((NH4)2CO3)	7.77
Epsom Salt (MgSO4)	9.50
Vinegar (acetic acid, CH3COOH)	2.21
Seltzer Water (carbonic acid, H2CO3)	3.97
Ammonia (ammonium hydroxide, NH4OH)	10.57

Seltzer: H+ concentration	0.000107
Vinegar: H+ concentration	0.006166
Ammonia: OH- concentration	0.000372

Answer 1