Different quantities of nitrogen oxide (NO) are listed below - VCE - SSCE Chemistry - Question 3 - 2007 - Paper 1

This option directly states the quantity of molecules. Therefore, the number of molecules is already given as:

$6 \times 10^3 \ molecules$

To convert grams to moles, we need the molar mass of NO. The molar mass of NO is approximately 30 g/mol. The number of moles in 6 × 10² g can be calculated as:

$n = \frac{mass}{molar \ mass} = \frac{6 \times 10^2 \ g}{30 \ g/mol} = 20 \ mol$

Using Avogadro's number, the number of molecules is:

$N = n \times N_A = 20 \ mol \times 6.022 \times 10^{23} \ mol^{-1} \approx 1.204 \times 10^{25} \ molecules$

Using Avogadro's number again, the total number of molecules in 6 mol of NO can be calculated as:

$N = 6 \ mol \times 6.022 \times 10^{23} \ mol^{-1} \approx 3.6132 \times 10^{24} \ molecules$