Chem Question; Conversion?!?!

Normal human blood has a cholesterol concentration of 200mg in 100ml of blood. Convert to
(a)micro grams/mL
(b) g/L
(c) ng/ micro L

(a) 1microgram = 10^-6g
so, 0.2g = (1/10^-6) x 0.2 = 0.2 x 10^6 micrograms = 2 x 10^5 micrograms
Conc in microgram /ml = 2 x 10^5 / 100 = 2000 microgram/ml

(b) 200mg = 0.2g
conc = (0.2 x 1000) / 100 = 2g/l

(c) 1 ng = 10^-9g
So, 0.2g = (1/10^-9) x 0.2 = 2 x 10^8 ng
1 microlitre = 10^-6 litre
0.1 litre = (1/10^-6) x 0.1 microlitre = 10^5 microlitre
conc = (2 x 10^8) / 10^5 = 2000 ng/microlitre

You have :
--------------------------------------…

C = 200 mg / 100 mL = 2.00 mg / mL

C = ( 2.00 mg / mL ) ( 1000 mug / mg ) = 2000 mug / mL <-------------------------------

C = ( 2.000 mg / mL ) ( 1 g / 1000 mg ) ( 1000 mL / L ) = 2.000 g / L <--------------------------

C = ( 2.00 mg / mL ) ( 10^6 ng / mg ) ( 1 mL / 1000 muL ) = 2000 ng / muL <---------------------