Which of the following correctly identifies steps used in the fractional distillation of petroleum?
the mixture is cooled, condenses, then heated and boils.
the mixture is cooled, boils, then heated and condense.
the mixture is heated, condenses, then cooled and boils.
the mixture is heated, boils then cooled and condenses.

The mixture is heated, boils then cooled and condenses

Explanation:

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation: