Conversion of ppb to ug

[jaylalawrence]

Hello,
I am hoping someone can help me to understand how the following equation results in ug. I know one ppb is equal to 1000 ug/mL but I don't really get this.
The equation is:
(#ppb * #mL)/ (10^9 * %carbon)
The % carbon is for one molecule.
I know this isn't a strictly math question but if anyone can explain I'd really appreciate it

 

[lev888]

Some context would be helpful. If this is from a book please post a screenshot.

 

[jaylalawrence]

It is an assignment for analysis of lab sample results. I am given a sample which is analyzed and the total carbon results are reported in parts per billion. The mL is the volume of the sample. The 10^9 is billion and the %carbon I have to look up based on what is in the sample. The equation is given in a written protocol by the teacher. I can just plug in numbers and do the equation but I don't get how the answer is in micrograms.

 

[lev888]

It is an assignment for analysis of lab sample results. I am given a sample which is analyzed and the total carbon results are reported in parts per billion. The mL is the volume of the sample. The 10^9 is billion and the %carbon I have to look up based on what is in the sample. The equation is given in a written protocol by the teacher. I can just plug in numbers and do the equation but I don't get how the answer is in micrograms.

ppb is mass per volume of liquid. If you multiply it by volume you get mass.