Question

Find the number of millimoles of $C{H}_4$ in a sample containing $1.2044\times {10}^{21}C{H}_4$ molecules.

• A. 2
• B. 0.002
• C. 20
• D. 0.02

Answer 1

The correct option is A 2

1 mole $C{H}_4$ contains $6.022\times {10}^{23}$ molecules of $C{H}_4$.
So, the number of moles that have $1.2044\times {10}^{21}$ molecules of $C{H}_4$
$=\frac{1.2044\times {10}^{21}}{6.022\times {10}^{23}}=0.002$
$=2$ milimoles