Is there a limit to the number of questions you can ask using the Card format?

2.Is there a limit to the number of questions you can ask using the 'card' format?

There is no limit, but we suggest optimizing the forms not to contain too many fields. Because the more fields you add, the more the form loads slowly in some browsers, especially for low-end PCs/laptops. 

Please be wary of the widgets as well since they are loaded in an iframe. More widgets mean more resources that need to be loaded in the form. 

I hope that helps.