How many people here have taken a class called 'Technical Communication'? I remember when I took the class I was startled when the young pretty lady informed me that I had a "personal" style of writing that could actually be badly misinterpreted.
For instance:
If you write, "What do you know about Chemistry?" you might have meant what level of instruction or experience does somebody have.
But what may be perceived is this type of thought, "You really don't know anything and are ridiculous." - Not your intent. Then add to that many people really will mean such things to your intended reader - confirming their suspicion at this time.
That would be considered "Aggressive Voice". If your reader online were to have been asked this repeatedly, they could become either irritated or emotionally hurt.
It would be much gentler to simply say, " Do you really like Chemistry? Have you studied it and enjoyed it? Because I want to know how much explanation we can share without causing us discomfort" And deliver a much more "Passive Voice". You can probably think of another few ways to say that too.
The thing is this new online world makes us act like we are speaking to our secretary in written notes constantly. Who would want to hurt their secretaries' feeling {or our online friends'}?
Here's a link to a description of one book and an online class.
http://www.io.com/~hcexres/tcm1603/acchtml/intro.html#about Your English instructor/Professor will probably be able to help you learn more about it also. But if not, an online course could help you save face and even your job sometime.
If you suspect you may have been guilty of this, cheer up. Everyone has made those mistakes at some time too.
We are but people.
Andy