How does w3wp.exe work with a web application?

If I create a web application and host it on Windows Server, then, as far as I understand, IIS processes the initial request and routes it to the appropriate website or application. I get the impression that an instance of w3wp.exe (workflow) is created for each application. IIS works with a worker process, which in turn works with a web application.

What happens if the application receives twenty requests per second? Will the workflow create twenty application instances to handle each request, or will there be a queue of requests being passed to one application instance when and when?

I suspect this is the latter. If so, would I think that the workflow will keep the application running while it receives requests?

I am trying to fully understand what a web application is doing when it is processing many of the current requests. I've already tried asking this question, but struggling with the wording, so hopefully it makes sense.

EDIT: Thanks to Mason, I realized that the answer was right in front of me! Web applications use DLLs that cannot run on their own. It is w3wp.exe (worker process) that calls the DLL to handle requests.