[susan53]

You don't need an article with singular nouns, when you have a quantifier such as no, each, or every. Compare these sentences :

We have a slight chance of succeeding.
We have every chance of succeeding.
They took each chance they were offered.
We don't have a chance of succeeding.
We have no chance of succeeding.

I never miss a free lunch.
I go to every free lunch which I'm invited to.
There is such a thing as a free lunch - but it's rare.
There's no such thing as a free lunch.