Question

How many g of Co(NO2)2 • 5 H2O are needed to make 432 mL of a 1.2 M solution?

Answer 1

$M=1.2M$

$V=432ml$

$M=\dfrac{moles}{volume(ml)} \times1000$

$1.2= \dfrac{moles}{432} \times 1000$

$moles= 0.518$

Now:

$weight=moles \times molar$ $mass$

$weight= 0.518 \times 210=108.78 gm$