Question

how many moles of methane (CH4) are in 7.31 x 10^25 molecules

Answer 1

molar mass of methane CH4

= C + 4 H  

= 12.0 + 4 x 1.008

= 12.0 +  4.032

= 16.042g/mol

7.31 x 10^25 molecules x             1 mole  CH4      = 121.43 moles

                                       6.02 x 10^23 CH4 molecules

121.43 moles CH4 are present.

       

Answer 2

Answer : The number of moles of methane are, 121.39 moles

Explanation : Given,

Number of molecules of methane gas = $7.31\times 10^{25}$

Now we have to calculate the number of moles of methane gas.

As, $6.022\times 10^{23}$ number of molecules of methane present in 1 mole of methane gas.

So, $7.31\times 10^{25}$ number of molecules of methane present in $\frac{7.31\times 10^{25}}{6.022\times 10^{23}}\times 1mole=121.39$ moles of methane gas.

Therefore, the number of moles of methane are, 121.39 moles