Name Prelaboratory Assignment 18 Section 25 pts 1 Consider t

Name Prelaboratory Assignment 18 Section 25 pts 1. Consider the following equilibrium in aqueous 2 Cro, (ag) +2H (a)CrO (a) H-00) In which the CrO, 2 ion is yellow and the CrO,2 is orange. a. the color in basic solution should be b. the color in acidic solution should be C. To shift the equilibrium to the right, 4 pts 4 pts should be added. 4 pts 2. In the equilibrium; dH > 0 PbC12 (s)- = Pb2+ (aq) + 2 Cl-(aq) a. Warning the solution should cause the PbCl; solid to (dissolve, become more insoluble). Explain! 4 pts b. the addition of HCI to this equilibrium will cause it to shift (left, right, no shift) Expalin! 4 pts 5 pts 3. We will also investigate the equilibrium; Fe3+ (aq) + SCN-(aq)- = FeSCN 2. (aq) colore could do in this experiment to determine whether AH for this reaction is either posit negative 2+

Solution

1) a) in basic solution equilibrium shifts towards left, color of the solution will be yellow.

b) In acidic solution equilibrium shifts towards Right, then dichromate will be dominant, hence color of solution should be orange.

c) To shift the equilibrium towards right, we should add reactants, so acid should be added.

2) a) delay H > 0 means heat absorbed in reaction, so this reaction is endothermic reaction.

If we warm the reaction then equilibrium shifts to the right.

b) If we add HCl then more amount of PbCl2 precipitate will be formed. So equilibrium shifts towards left side.

3) If we perform the given reaction in bomb calorimeter we can determine the enthaply of the reaction Delta H of the reaction. If temperature of calorimeter increases the reaction has negative Delta H, if calorimeter Temperature decreases then the reaction has positive Delta H value.