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Writing Chemistry Equations

1. Calculate the pH at the equivalence point in a titration between 10.00 mL of acetic acid(0.100 mol/L) and sodium hydroxide (0.100 mol/L).

2. A reaction was carried out in an acidic medium. The equation for the reaction was given as Fe 3+(aq) + HSCN(aq) <----> FeSCN 2+(aq) + H+(aq). Write the equilibrium constant expression for this reaction as written.

3. Under certain conditions, the product of the reaction between iron(III) ions and thiocyanate ions is the dithiocyanatoiron(III)ion, Fe(SCN)2 +.
a) Write an equation for the reaction in which dithiocyanatoiron(III) ions are produced.

b) Write the equilibrium-constant expression for the equation written in part A.

4. When a few drops of sodium fluoride solution are added to a solution containing iron(III) ions a colorless solution is obtained.

Fe 3+(aq) + 6f -(aq) <----> FeF6 3-(aq)
(pale yellow) (colorless)

However when a few drops of sodium chloride are added to a solution containing iron(III) ions a pale yellow solution is obtained, with the yellow color deepening as more sodium chloride is added.

Fe 3+(aq) + 4Cl -(aq) <----> FeCl4 -(aq)
(pale yellow) (intense yellow)

Predict what will occur, if a solution of sodium fluoride is added to the solution prepared from the iron(III) and sodium chloride solutions. Justify your prediction in terms of Le Chatelier's principle.

5. A cell is represented by: Zn(s)| Zn 2+(aq)(1 mol/L) || Cu 2+(aq)(1mol/L)| Cu(s)

In such representations the anode is always written first, with the single vertical lines (|) representing the phase boundaries and the double vertical lines (||) representing the salt bridge. For each of the following voltaic cells write the overall reaction and determine the voltage produced.
a) Zn(s)| Zn 2+(aq)(1 mol/L) || Cu 2+(aq)(0.20 mol/L)| Cu(s)
b) Pb(S)| Pb 2+(aq)(0.20 mol/L) || Cu 2+(aq)(1 mol/L) | Cu(s)

6. The chloroplatinate ion may be represented by the formula PtCl4 x-.
When an aqueous solution containing chloroplatinate ions was electrolyzed for 2.00 hours, using a current of 0.0750 A, 0.546g of platinum was deposited on the cathode. Determine the charge on the chloroplatinate ion.

7. Write the equations for each of the following reactions:
a) the reaction of salicylic acid with methanol (the product, methyl salicylate, is known as "oil of wintergreen")
b) the reaction between acetylsalicylic acid and sodium hydrogen carbonate
c) the reaction between the product from reaction b) and hydrochloric acid.

Solution Summary

The solution answers different questions and assists in writing chemistry equations.