Phenylephrine is a nasal decongestant and is the active ingredient in Sudafed, which contains phenylephrine hydrochloride (PEHCL). The conjugate acid (PEH+) of phenylphrine has a pKa = 5.5. At a physiological pH of 7.4. what is the ratio of concentrations, [PE]/[PEH+]?

The ratio of concentrations is 79.4

Explanation:

Using Henderson-Hasselbalch equation we can solve the [PE]/[PEH+] ratio:

pH = pKa + log [A-] / [HA]

Where pH is 7.4

pKa of the phenylphrine is 5.5

[A-] is the weak base = [PE]

And [HA] is the conjugate acid [PEH+]

Replacing:

7.4 = 5.5 + log [PE] / [PEH+]

1.9 = log [PE] / [PEH+]

79.4 = [PE] / [PEH+]

The ratio of concentrations is 79.4

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.

the answer is:  

line graphs show patterns in data with variables that change over time; whereas, circle graphs show data as parts out of a whole (such as out of 100%).