24 FIRST YEAR COURSE IN GENERAL SCIENCE 



EXERCISE XVI (Textbook 155) 

 HEATING WITH GAS FLAMES 



APPARATUS: Bunsen burner, thermometer, evaporating 

 dish. 



DIRECTIONS FOR WORK: 



(1) Put into a porcelain dish 100 cu. cm. of water, after 

 noting its temperature; record its temperature after heating 

 5 min. with a luminous flame. (Stir the water with the 

 thermometer while -heating and keep the bulb of the ther- 

 mometer in the water until after reading and recording the 

 temperature.) 



(2) With fresh water, repeat the work of Case 1, using a 

 non-luminous flame. 



Case 1. Temp, of water at start Temp, at end 



Case 2. Temp, of water at start Temp, at end 



RESULTS 



1. What kind of flame is best for cooking purposes? Why? 



2. Why does the flame give more heat if air can enter the 

 gas tube and mix with the gas before burning? 



3. The lampblack deposited on the porcelain comes from 

 the flame. Is its color the same while in the flame? Why? 



4. From this, give an explanation of light from a flame. 



EXERCISE XVII (Textbook 164) 

 A PRODUCT OF OXIDATION 



APPARATUS: A piece of charcoal (which is nearly pure 

 carbon), a combustion spoon, a bottle of air, limewater, a 

 beaker or tumbler. 



DIRECTIONS FOR WORK: If no change is observed in 

 the following work, the record should be "no apparent 

 change." 



