.246 SMITH'S INTERMEDIATE CHEMISTRY 



1. Why do some chemical actions cease, while still incomplete? 

 Answer: They are reversible. 



2. What explains the position of the equilibrium point? An- 

 swers: (a) Equal effects of opposed molecular actions; (6) Equal- 

 ity in speed of opposed reactions. 



3. What will displace the equilibrium point? Answer: (a) 

 Change in concentration of one (or more) of the substances; (6) 

 Change in the temperature. 



Exercises. 1. Explain the completeness of the action by 

 which hydrogen chloride and water, respectively, are formed by 

 direct union of the elements. 



2. Explain the completeness of the action by which silver 

 chloride (p. 131) is formed. 



3. Explain why the decomposition of potassium chlorate is 

 complete. 



4. In view of the statement on p. 16, explain why mercuric 

 oxide is completely decomposed by heating. 



5. Why can magnetic oxide of iron be reduced completely by 

 a stream of hydrogen (p. 57), and iron oxidized completely by a 

 current of steam (p. 51)? 



6. With the phosphorus pentachloride system, say at 250, 

 what effect would suddenly enlarging the space containing a given 

 amount of the vapor produce? What would be the effect of 

 diminishing the space? What would be the effect of introducing 

 additional chlorine into the same space (p. 234)? 



7. Are the following systems in equilibrium or not: (a) a cap- 

 tive balloon pulling at its rope, (b) a balloon floating freely 

 in cooling air, (c) a man wearing a heavy suit in winter only, 

 (d) a woman changing to a velvet hat in August and to a straw 

 hat in February? What is the stress in each case? In which 

 systems does a reaction take place which opposes the effect of the 



