

HYDROGEN 



39 



Is it combustible? (6) What is formed when H is burned? 

 (7) How do you know that this product is formed ? (8) From 

 what compound was the H obtained ? (9) What caused the H 

 to be liberated from this compound ? (10) Why are mixtures of 



Fig. 18. Thrusting burning splinter into hydrogen. 



H and O very explosive? (n) What other acids could be used 

 in the preparation of H ? (12) What other metals could be used 

 in the preparation of H ? (13) Give the equation for the reac- 

 tion of the Zn and HC1. (14) What do these tests prove in re- 

 gard to the character and properties of the element H ? 



41. Properties. Physically, hydrogen is characterized 

 as a colorless, odorless, and tasteless gas. It is the 

 lightest in weight of any of the elements, and for that 

 reason is taken as the standard for the atomic weights. 

 At a low temperature, and under pressure, hydrogen can 



