Let's write that m = molarity in units of moles/liter and n = number density = N/V, the number of molecules divided by the volume they are in, in units of molecules/m3. Since m and n must be proportional, we expect there is an equation n = αm where α is some constant. Find the numerical value of α and its units (keeping "moles" and "molecules" as units).

Respuesta :

Answer:

[tex]\alpha=6.022*10^{20}\frac{m^3 * molecules}{L * mol}[/tex]

Explanation:

Hi, the question states that there is a proportional relation between m (molarity) and n (number density), by following formula:

[tex]m=\alpha*n[/tex]

The units of alpha ([tex]\alpha[/tex]) must help to balance the units of m and n.  

1) First in both sides there are volume units liter and m3. So we need to express all volume in the same unit. Knowing that: [tex]1 m^3=1000 L[/tex]

2) We also need to find a relation between mol and molecules. The relation is given by the Avogadro's number: [tex]A=6.022*10^{23} \frac{molecules}{mol}[/tex]

With this two numbers we can balance the units and find the value of [tex]\alpha[/tex] :

[tex]\alpha=\frac{1 m^3}{1000 L}*6.022*10^{23}\frac{molecules}{mol}[/tex]

[tex]\alpha=6.022*10^{20}\frac{m^3 * molecules}{L * mol}[/tex]

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