A chance of a lifetime

2.For many athletes, the Olympics is a once-in-a-lifetime opportunity/chance.

Are 'chance' and 'opportunity' interchangeable in the two sentences above?

Is there any subtle difference between the two terms here?

Thanks a lot!

I know 'chance' have some different usages. According to the dictionary, it can mean "a time or situation which you can use to do something that you want to do." For example:

Ralph was waiting for a chance to introduce himself.

I think 'opportunity' has the similar meaning like 'chance' here. Can I replace 'chance' with 'opportunity' as in

Ralph was waiting for an opportunity to introduce himself.

Is there subtle difference between 'chance' and 'opportunity' here?

Thanks.

2) our only chance/opportunity of escape

3) I never get/have a chance/an opportunity to relax these days.

4) I'd like to take this opportunity/chance to thank you for all your hard work.

5) I'd like to seize this opportunity/chance to thank you for all your hard work.

6) Denise never misses the chance/opportunity of a free meal.

7) He was given a second chance/opportunity to prove his abilities.

8) I didn't get/have a chance/opportunity to speak to her.

9) If you give me a chance/an opportunity to speak, I'll explain.

10) Society has to give prisoners a second chance/opportunity when they come out of jail.

11) He left and I missed my chance/opportunity to say goodbye to him.

12)If I had  a chance/an opportunity to become a university studednt, I would study as hard as possible.

Thanks.

Sorry, I didn't see this before. 

This is how I expect to hear them. "I'd like to take this opportunity to..." is so fixed that "chance" sounds odd to me there. You "miss an opportunity." Most others are interchangeable.  

 If someone "gives you a chance" it has more of a sense of proving yourself after you have somehow started out with the idea that you are not suitable. You don't seem like you'd be a suitable romantic partner, but she'll give you a chance; you made a mistake when you did this job before, but they'll give you a chance to make it right. In contrast, someone who gives you an opportunity does not have the preconceived idea that you won't succeed.

Anonymous

1) I can explain everything if you'll just give me a chance/an opportunity.

2) our only chance/opportunity of escape

3) I never get/have a chance/an opportunity to relax these days. "get a chance" is my preference, but "opportunity" doesn't sound weird.

4) I'd like to take this opportunity/chance to thank you for all your hard work.

5) I'd like to seize this opportunity/chance to thank you for all your hard work.

6) Denise never misses the chance/opportunity of a free meal. -- Neither. Maybe "the opportunity to accept a ..."?

7) He was given a second chance/opportunity to prove his abilities. -- If he messed up the first time, then "chance." If he did well the first time, then "opportunity."

8) I didn't get/have a chance/opportunity to speak to her. -- Either

9) If you give me a chance/an opportunity to speak, I'll explain.

10) Society has to give prisoners a second chance/opportunity when they come out of jail.

11) He left and I missed my chance/opportunity to say goodbye to him. -- Either

12)If I had  a chance/an opportunity to become a university studednt, I would study as hard as possible. -- Here, for some reason, "Had a chance" seems like a remote possibility.