Question

How do you identify the opposite and the absolute value of a rational number

Answer 1

"The absolute value of an integer is its distance from zero on a number line. For example, the absolute value of -8 is +8, because -8 is 8 units from zero on the number line. Note that the absolute value of any positive or negative integer is positive." http://www.mathhelp.com/how_to/integers_and_the_number_line/opposites_and_absolute_value/

Answer 2

Opposite:
Just change the sign.
If it's a positive number, make it negative.
If it's a negative number, make it positive.

Absolute value:
Even easier.
Just throw away the sign, and you have it.