17248
Electrophoretic study revealed that alpha - chains of gelatin in films became lowered with increasing H ( 2 ) O ( 2 ) concentrations used for bleaching .
 H ( 2 ) O ( 2 )
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 H ( 2 ) O ( 2 )