148 EXPERIMENTAL GENERAL SCIENCE 



11. In baking, cream of tartar and baking soda are often mixed 

 together and these, in the presence of moisture effervesce and give off 

 much carbon dioxide. It is this gas, increased in volume by the heat 

 of baking, that causes cake, biscuit, and the like to rise. When sour 

 milk is used in baking, cream of tartar may be omitted, but not the 

 soda. Why? 



12. When molasses is used in baking, the addition of soda alone will 

 make the cake light. What substance do you infer must be present in 

 the molasses? 



13. All baking powders are mixtures of an acid and a carbonate, the 

 latter a salt of carbonic acid and sodium. Usually a small quantity of 

 corn starch is added to keep them apart. Why do they not give off their 

 contained carbon dioxide if the can is kept closed? 



14. If baking powder is left exposed to the air, it deteriorates. Why? 



15. Why are baking powders always stirred into the flour before 

 moisture is added? 



