Question

How many molecules of liquid methanol are in 10.00 mL of methanol, given its density is 0.7918 g/mL?

Answer 1

$d=0,7918\frac{g}{mL}\\ V=10mL \ \ \ \ \ \ \ \ \ \ \ m=dV=0,7918\frac{g}{mL}*10mL=7,918g\\\\ 6,02*10^{23} \ \ \ \ \ \ \ \Rightarrow \ \ \ \ 32g\\ N_{x} \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \Rightarrow \ \ \ \ 7,918g\\\\ N_{x}=\frac{6,02*10^{23}*7,918g}{32g}\approx1,49*10^{23}$