"You can't have web space without web hosting account." first of all, you must need a web hosting account to run a website. the hosting account includes such as domains, database, email, web spaces, bandwidth and all the require things that need for a website.
Webspace is like a hard drive in your computer while web hosting is like the computer itslef. So in order to have a web space (hard drive), you have to get a web hosting (whole computer) first. Hope that make sense
Web hosting is the service that makes your domain / website available to the world on the internet. Web space id the amount of storage you are allowed with your host.
web hosting is the service of hosting your website while web space is just the actual disk ammount on hosting server.