COMBUSTION AND OXIDATION 79 



10. Keeping the jar upright, remove the candle and pour into the jar 

 about 10 cubic centimeters of lime-water. Shake it and note the result. 

 With what substance in the candle has the oxygen of the air united? 



11. Place the candle end on the table, light it and hold the mouth of a 

 cold dry bottle over the flame. What soon covers the inside of the 

 bottle? 



12. Press a white card down on the candle flame in such a way that the 

 tip of the flame is flattened out against the card. When the card begins 

 to char, remove it and examine. Where was the flame the hottest? 

 Why? 



13. Press a clean white dish or sheet of metal down on the candle 

 flame for a few seconds. What chemical element is deposited on the 

 object? 



14. Why was it not burned? 



16. Light a candle and after it has been burning a few seconds, blow 

 it out and immediately hold a lighted match about an inch above the 

 wick in the smoky substance rising from it. What inference do you make 

 as to whether the burning substance is a solid, a liquid, or a gas? 



16. Hydrogen and oxygen unite with much heat to form water. Can 

 you tell why such a flame never smokes? 



17. Blow your breath through a straw or glass tube into half a test- 

 tube of lime-water. What chemical substance in the breath does this 

 show? 



18. In the process of making wood alcohol, the wood is placed in 

 an air-tight cylinder and heated very hot. When the cylinder is opened 

 the wood, instead of being burned up, is found to have become charcoal. 

 Explain. 



