You are informed of something
You come to know something
You are aware of something
Would anyone explain the difference between those? And whether or not one can use them interchangeably? If so, when?
Consider there’s your colleague named Jack. One bad day, he has been sacked. In this context, I’ll try to answer your questions.
You asked the differences. Here are they.
You are informed (-sense#1) of something ~ You are informed of Jack’s sacking.
Either someone told you or you got this information from somewhere (maybe, an email or something for example). Point to note: You did not do any effort to know this piece of news.
You come to know something ~ You come to know that Jack has been sacked
This is quite similar to the above one but when you inform someone, it’s official and when you come to know something, it could be through gossip, general talk or things the like. Point to note: You may or may not do any effort for this. This may come as your efforts, coincidence (employees were talking about it and suddenly you came) or luck. In other words, say, you enter into gossip that has been already going on and there, the topic of Jack’s sacking comes (with no effort, you came to know this news) or you toss a topic of current sacking in the company and someone tells you that Jack has been sacked (you made some efforts to know who all are been sacked).
You are aware of something ~ You are aware of Jack’s sacking
This means Jack’s sacking is probably declared and well known. You know or realize this news (sense #1, sense #2 is also possible but then it’ll be in a different context) and you are pretty well aware of it. In this context, being aware means the person who’s talking to you is probably confirmed that Jack’s sacking is not a secret to you anymore. And again, you are aware of it.
Now the second question:
No, they are not interchangeable all the time.
You cannot be aware of something unless that something is being informed to you. Check the example there:
"I don't think people are really aware of just how much it costs." True, you have to inform them to make them aware.
Likewise, if you come to know something, it does not necessarily mean that someone informed you. The knowledge of that something has come to you because of your efforts, luck or coincidence.
Hope this helps.