 # Converting Hydrogen Ion Concentrations to pH Practice Problems.

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Converting Hydrogen Ion Concentrations to pH Practice Problems

Practice Problems 1) Calculate the pH of each solution, given the hydrogen ion concentration. a) [H + ] = 0.0027 mol/L pH = 2.57 b) [H + ] = 7.28 x 10 -8 mol/L pH = 7.138 c) [H + ] = 9.7 x 10 -5 mol/L pH = 4.01 d) [H + ] = 8.27 x 10 -12 mol/L pH = 11.082

Practice Problems 2) [H + ] in a cola drink is about 5.0 x 10 -3 mol/L. Calculate the pH of the drink. State whether the drink is acidic or basic. pH = 2.30, acidic 3) A glass of orange juice has [H + ] of 2.9 x 10 -4 mol/L. Calculate the pH of the juice. State whether the result is acidic or basic. pH = 3.54, acidic 4) [H + ] in a dilute solution of nitric acid is 6.3 x 10 -3 mol/L. Calculate the pH of the solution. pH = 2.20

4 Acid-Base Reactions

5 Acid & Metal Reaction Single displacement reaction Hydrogen in the acid behaves like a metal, producing hydrogen gas and an ionic compound (salt) What is produced when magnesium is reacted with hydrochloric acid? Mg (s) + 2 HCl (aq)  H 2(g) + MgCl 2(aq)

6 Acid & Carbonate Reaction Double displacement reaction First producing carbonic acid which is extremely unstable and further decomposes to form carbon dioxide and water What is produced when hydrochloric acid is added to calcium carbonate? HCl (aq) + CaCO 3(s)  H 2 CO 3(aq) + CaCl 2(aq)  CO 2(g) + H 2 O (l) + CaCl 2(aq)

7 Acid & Base Reaction (Neutralization) Double displacement reaction Produces water and a ionic compound (salt) What is produced when hydrochloric acid is added to potassium hydroxide? HCl (aq) + KOH (aq)  H 2 O (l) + KCl (aq)

8 What is the TOTAL ionic equation for the above reaction? H + (aq) + Cl - (aq) + K + (aq) + OH - (aq)  H 2 O (l) + K + (aq) + Cl - (aq) What is the NET ionic equation? H + (aq) + OH - (aq)  H 2 O (l)

9 Acid & Ionic Compound Reaction Double displacement reaction Precipitation reaction with some ionic compounds (rare!) What is produced when hydroiodic acid reacts with lead(II) nitrate? 2 HI (aq) + Pb(NO 3 ) 2(aq)  PbI 2(s) + 2 HNO 3(aq)

10 Neutralization PRACTICE 1 Using volumetric analysis, 13.84 mL of hydrochloric acid, HCl (aq), just neutralizes 25.00 mL of a 0.1000 mol/L solution of sodium hydroxide, NaOH (aq). What is the concentration of the hydrochloric acid?

11 Neutralization PRACTICE 2 What volume of 0.250 mol/L sulfuric acid, H 2 SO 4 (aq), is needed to react completely with 37.2 mL of 0.650 mol/L potassium hydroxide, KOH (aq) ? Textbook Question p. 399 # 6