PRECIPITATION, FILTRATION, AND DISTILLATION 143 



Practical Exercises 



1. Make a solution of about one-half gram of lead nitrate in 10 cubic 

 centimeters of distilled water. To this solution add an equal volume of 

 salt water. What happens when the two solutions are mixed? 



2. What term describes the matter you now have in the bottom of the 

 test-tube? 



3. Place a filter paper in a glass funnel supported by a ring stand 

 and pour the mixture you have made into it, catching the filtered liquid 

 in a beaker. What part of the mixture fails to pass through the filter? 



4. Dissolve some salt in water and filter through a clean filter paper. 

 Taste the liquid that filters through. Does the salt filter out? Why? 



6. Shake up a crystal of potassium permanganate in a test-tube and 

 filter. Was this substance dissolved in the water or merely held in 

 suspension? 



6. How could you separate a mixture of salt and sand? 



7. How could you separate a mixture of salt and water? 



8. In sugar making, the syrup is clarified and its color removed by 

 being passed through bone-black, a charcoal made from bones. Explain 

 how the syrup can be clarified in this way. 



9. Filters for home use are often made of a layer of charcoal, others 

 have a bottom of fine porous stone through which water filters. What 

 do you infer as to the need for frequently cleaning such niters? 



10. Cisterns are often divided by a brick wall, the rain water coming 

 in on one side of the wall and the house supply being pumped away 

 from the other. Of what advantage is this? 



