How many molecules are in 12 grams of methane (ch 4 )?

To calculate number of molecules, we first need to calculate the number of moles of methane.

Number of moles of methane = \frac{Given mass}{Molar mass of methane}

Molar mass of methane= 16.04 g/mol

Given mass of methane= 12 g

Number of moles of methane=\frac{Given mass}{Molar mass of methane}

=\frac{12}{16.04}

= 0.74 mol

Number of molecules of methane = 0.74\times 6.023 \times 10^{23}

= 4.5 × e²³

the answer is symmetrical : )