moles = grams/molar mass
molarity = mols/L
Post your work if you get stuck.
what is the molarity of the solution which contains 5.0g of NaOH(formar weight=40g/mole)dissolved in water to make 200 ml of soluitons?
2 answers
m=mols/L
first, get the no. of moles.
n=wt/mw
where n = no. of moles
wt = weight
mw = molecular weigth
n = 5.0g / 40 g/mol
cancel the grams, so the left unit is mol.
Ans. n=0.125mol
You can now get the molarity of the solution,
m = n/L
where m = molarity
m= 0.125mol / 200ml
*conversion:
1L=1000ml
200ml x 1L/1000mL
==> 0.2L
you can now solve the molarity
m= 0.125mol / 0.2L
ANS: m = 0.625mol/L
first, get the no. of moles.
n=wt/mw
where n = no. of moles
wt = weight
mw = molecular weigth
n = 5.0g / 40 g/mol
cancel the grams, so the left unit is mol.
Ans. n=0.125mol
You can now get the molarity of the solution,
m = n/L
where m = molarity
m= 0.125mol / 200ml
*conversion:
1L=1000ml
200ml x 1L/1000mL
==> 0.2L
you can now solve the molarity
m= 0.125mol / 0.2L
ANS: m = 0.625mol/L