Concentrations: density, relative density, percentage, molarity, mass concentration

Tutorial 6

        

Use this schematic "lattice" and →    the definitions to resolve the following exercise:

Exercise Calculate the number of moles of sodium hydroxide in $ 3050 \; mL $ of a $21.90\%$ solution of density $1.240\frac{g}{mL} $. Solution (Click): Scheme and Formulas: .......... Calculation: ..........$m_{S}=\rho_{S}\cdot V_S$ $=$ $1.240\cdot 3050=3782\;g$
$m_{so}$ $=$ $\frac{m_S\cdot \%_{so} }{ 100}$ = $\frac{3782\cdot21.90}{100}$ = $828.3 \; g$
$n_{so}$ = $\frac{m_{so}}{M_{so}}$= $ \frac{828.3}{ 40.0}=20.7\; mol$
because $M_{so}=M_{NaOH}=40\frac{g}{mol}$