How many molecules are present in a drop of ethanol, c2h5oh, of mass 2.3*10^-2.3g? (NA=6.0*10^23mol^-1)

explain why

a) 3.0*10^19

b) 3.0*10^20

c) 6.0*10^20

d) 6.0*10^26

3.0 * 10²⁰ molecules

Explanation:

Given dа ta:

Mass of ethanol = 2.3 * 10⁻²°³ g

Number of molecules = ?

Solution:

Number of moles of ethanol:

Number of moles = mass / molar mass

Number of moles = 2.3 * 10⁻²°³ g / 46.07 g/mol

Number of moles = 0.05 * 10⁻²°³ mol

Number of molecules:

One mole = 6.022 * 10²³ molecules

0.05 * 10⁻²°³ mol * 6.022 * 10²³ molecules / 1 mol

0.30 * 10²⁰°⁷ molecules

3.0 * 10¹⁹°⁷ molecules which is almost equal to 3.0 * 10²⁰ molecules.