A: This will NOT work on 3/4" copper pipe. The INTERIOR diameter of copper pipe is 3/4" but the EXTERIOR where you would slip the hose over the pipe is 7/8". You might be able to lube the hose up and force it on but that would stress the rubber and lead to early failure.
A: The maximum working pressure is 80 psi.
A: Not sure of the pressure rating, but it is more than enough for continuous water pressure, such as for a garden hose extension. However, I wouldn't use as a heater hose for a automotive application.
A: -40 to 190 degrees Fahrenheit or so the description says.