Question

Calculate the number of molecules present in each of the following samples.

4.75 millimoles of phosphine, PH3

Answer 1

Answer:

$2.8*10^{21}moleculesPH_{3}$

Explanation:

1. Convert from milimoles to moles:

$4.75millimolesPH_{3}*\frac{0.001molPH_{3}}{1millimolPH_{3}}= 4.75*10^{-3}moles$

2. Use the Avogadro´s number to find the number of molecules in one mol:

$4.75*10^{-3}molesPH_{3}*\frac{6.022*10x^{23}moleculesPH_{3}}{1molPH_{3}}=2.8*10^{21}moleculesPH_{3}$