316 ELEMENTARY GENERAL SCIENCE en. xxm 



9. Mention three minerals consisting of silica, and state by what 

 characteristic feature you would recognise them. 



10. How would you attempt to prove that limestone, marble, and 

 calcite were essentially similar compounds ? [The student is advised 

 to consider well what experiments he has previously carried out with 

 calcium carbonate.] 



11. Limestone is dissolved in hydrochloric acid and the solution 

 evaporated. Briefly describe the appearance and properties of the 

 substance which you would expect to be thus obtained. 





