Android Phone (hey Google) Question

What's the voice command to use when you want to call up (to the screen) a particular contact?

What's the voice command to use when you want to navigate to a particular contact's address?

Of course, I made sure I have the address written as part of contact info. But sometimes, asking Google to navigate to "Joe Blow home address' will work (Google responds with a "OK, let's go!" -- but other times, "Mary Jane home address' will get the Google response, "Here's what I found about Mary Jane home address on the web" - or something similarly useless.