21499
gamma as a function of [ OH ] can be described by a Langmuir - Hinshelwood model , neglecting bulk processes , suggesting that despite its strong reactivity , OH is mobile on surfaces prior to reaction .
 Chemical: OH; Chemical: OH
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: OH; Chemical: OH