This lesson is the second of five lessons that focus on nominal phrases that deserve special attention.
As a noun, きかっけに means "trigger" or "prompt". In the speech modal きっかけに it means "take the opportunity to...".
What was it that triggered you to begin studying Japanese?
To raise opposition in taking advantage of the case.
Take the accident to bring the family back together.
契機 means "opportunity" and is in the speech modal を契機に meaning "taking the opportunity".
Taking the opportunity and starting a new business.
Violence is occurring in taking the opportunity of suppressing speech in Bahrain.