Question

how do i convert 0.00183338433 g/mL to mM? and putting it in 4 significant numbers. thank u

Answer 1

sorry i forgot to put that the chemical formula is C8H14N2O3S

Answer 2

to convert grams to mols you need to know molecular weight from periodic table of each of the elements in the compound.
C = 12.011 g/mol
H = 1.008 g/mol
N = 14.007 g/mol
0 = 15.999 g/mol
S = 32.06 g/mol

each of these numbers indicates how much 1 mol weighs in grams

now in your compound there are 8 Cs, 14 Hs, 2 Ns, 3 Os and 1 S

so 1 mol of your compound weighs
8*12.011 g/mol+
14*1.008 g/mol+
2*14.007 g/mol+
3*15.999 g/mol+
1*32.06 g/mol=
218.271g/mol

0.00183338433 g/mL * (1mol/218.271g) (set it up so the grams cancels and the mols are left)

so 0.00183338433/218.271=8.39958*10^-6mol/mL

now convert to desire units:

8.39958*10^-6mol/mL*(1000mmol/1mol)*(1000mL/1L)
(again set it up so units cancel properly)
1000*1000 = 10^6 which cancels the 10^-6

thus 8.39958mmol/L or in other words 8.39958mM

and finally to four scientific figures
8.400mM