Question

Calculați masa și volumul a 5 moli de apă.

Answer 1

M H2O=2•1+16=18 uam
1 mol H2O =18 g
n=m/M<=>5=m/18=> m=5•18=90 g H2O
n=nr.de moli
m=masa in data in problema
M=masa atomica
¶=densitate
¶=m/V<=>V=m/¶<=>V=90/1=90 cm^3= 9 dm^3=9 l
¶ apa=1 g/cm^3

Answer 2

$\nu_{H_2O}=5 \ moli \\ \rho_{H_2O}=1 \ 000 \ kg/m^3=1 \ g/ml \\ \boxed{m_{H_2O}-?} \ \ \ \boxed{V_{H_2O}-?} \\ \bold{Rezolvare:} \\ \boxed{\nu=\frac{m}{M}} \ \ \ \ \ \ \boxed{\rho=\frac{m}{V}} \\ M_{H_2O}=1 \cdot 2+16 \cdot 1=2+16=18 \ g/mol \\ m_{H_2O}=\nu_{H_2O}\cdot M_{H_2O}=5 \ moli \cdot 18 \ g/mol \\ \Rightarrow \boxed{m_{H_20}=90 \ g} \\ V_{H_2O}=\frac{m_{H_2O}}{\rho_{H_2O}} \\ V_{H_2O}=\frac{90 \ g}{1 \ g/ml} \\ \Rightarrow \boxed{V_{H_2O}=90 \ ml}$