SOLUTIONS 137 



19. Account for the lack of pungency or "bite" in a glass of carbonated 

 water that has stood for some time exposed to the air. 



20. Household ammonia consists of ammonia gas dissolved in water. 

 When is the cork likelier to pop out of the ammonia bottle, on a cold or 

 on a warm day? Why? 



21. How does adding more of a solute affect the density of a solution? 



22. Which would freeze earlier in winter, a shallow lake or an equally 

 shallow inlet from the ocean? Why? 



23. Why does salting boiling water stop the boiling for a short time? 



24. Suppose that on a cool night, ice should form (crystallize) on a 

 quantity of vinegar or sugar and water. Do you infer that the remainder 

 of the solution would be weaker or stronger than before? Why? 



25. Water is often said to "purify itself" by freezing. Explain. 



26. When the sea in the arctic regions freezes, which do you infer 

 contains the more salt, the water or the ice? 



27. What can you say of the seriousness of burns from boiling syrup 

 and the like? 



28. Does putting sugar in your coffee, cool or warm it? 



29. Why, in fixing the boiling point on the thermometer, must pure 

 water be used? 



30. Explain the use of charcoal in deodorizing sick rooms. 



31. Milk, butter, and other foods left near strong-smelling substances 

 will take up their odors. Explain how this occurs. 



