These two words can be confusing. Here's a good rule of thumb:
Use "that" whenever the identity "that" is replacing is known to the speaker. Examples:
I will read the book that is written by my favorite author. (not: "which is written..")
All that I can see from here is beautiful.
She didn't even apologize, and that is why I am angry. (not: "apologize, which is why...")
Use "which" whenever the speaker does not know what "which" is. Examples:
Which route will we take to get there?
I do not know which [one] is the better car.
Difference between paging and what?
just difference
the difference between webcontrol and literal?
What is the difference between strong and brave
what is the difference between mg and mgl
difference between as on and as at
What is the difference between Florida and California What is the difference between Florida and California
what's the difference between physician and doctorwhat's the difference between physician and doctor what's the difference between physician and doctor
Difference between paging and what?
difference between enterprise and corporation
difference between enterprise and corporation
The difference between a shogun and a samurai is like the difference between a king and a knight.
just difference
Difference between it and what?
what is the main difference between polyethylene and polyesters what is the main difference between polyethylene and polyesters
The difference between Disneyland and Disneyworld is that Disneyland is in California and Florida is in Disneyworld. This is the difference between Disneyland and Disneyworld.
The difference between 9538 and 6743 is 2795.