Depending on how you were added to a Google space, you will either be added to the space automatically, or be invited to join.
If you have been added to a space directly, and not as part of a Google Group, you will be added to the space automatically and it will be listed under Spaces in Google Chat.
You can position the mouse over a space name to show ellipses, which you can click on to hide a space you no longer wish to view in your list.
If you’re invited to a space as part of a Google Group, you will receive an email message which includes a link to join the space. Rather than joining the space immediately, you can preview the space to see if it will be relevant to you:
Click on the + to right of the Spaces header on the left-hand slide of the screen
Choose Browse spaces
Click on the space you’ve been invited to - it will show at the top of the list
Position the mouse over the space name and choose Preview to view conversations in the space without the ability to respond to messages.