Copper Sulfate 63 



which estabhshes the relationship between the copper 

 and the gas given off. The number of giams repre- 

 sented by the symbol NO2 occupies 22.4 hters (molec- 

 ular volum). Now we have the complete data for the 

 ratio which is 



6Cu 381.6 grams of copper 



4(22.4 hters) 89.6 liters of gas 



As 10 grams of copper were used in the experiment the 

 following proportion will give the number of hters of 

 gas produced: 



?51^ = 12 = Uters of either NO or NO2. 

 89.6 X 



5. What is necessary to make copper dissolv in 

 acids? 



6. What are the uses of copper sulfate? 



7. What are two tests for copper? What compound 

 in each case is used to recognize the copper? 



8. How can the number of copper ions in a solution 

 be reduced to a negligible quantity? 



9. What oxid, or oxids, of nitrogen are red? What 

 colorless? 



10. How many liters of nitrogen dioxid were given 

 off in this experiment? Of nitric oxid oxidized by the 

 air? How many grams of each? 



