8 



PLANT BIOLOGY 



Preparation of carbon dioxid: Into a flask put some pieces 

 of marble, and insert a stopper through which passes a thistle 



tube and a delivery tube like that 

 used in the preparation of oxygen. 

 Pour into the thistle tube diluted 

 hydrochloric acid until the lower 

 end of this tube is covered. Col- 

 lect a bottle of carbon dioxid in 

 .the same way that oxygen is col- 

 lected, keeping the mouth of the 

 bottle closed with a glass plate or 

 cardboard. (Fig. 2.) Prepare a 

 \ \\ fl^ / Bottle of carbon dioxid as directed, 

 \ x^y / and allow it to stand till all fumes 

 FIG. 2. -Preparation of carbon have disappeared, before answering 

 dioxid or of hydrogen. the following questions. 



1. Examine a bottle of carbon dioxid and state whether it 



- is a solid, a liquid, or a gas. Compare this gas 

 and oxygen as to color. 



2. Light a splinter of wood and thrust it into the bottle of 



carbon dioxid. 

 a. Tell what was done and describe the effect of the carbon 



dioxid upon the burning splinter. 

 6. How was the burning splinter or carbon affected by 



oxygen? 



3. Generate some carbon dioxid as suggested above and pass 



it through the delivery tube into a test tube of 

 clear lime water. Tell what was done and describe 

 the effect of carbon dioxid on lime water. (Carbon 

 dioxid is the only gas that affects lime water in this 

 way ; hence the latter is a reliable test for carbon 

 dioxid.) 



4. State the four characteristics of carbon dioxid which you 



have learned from these experiments. 



5. Place in a bottle of pure oxygen a piece of glowing 



carbon, and allow it to burn as long as it will. 

 When the carbon ceases to burn, quickly remove 



