C2H4 and C3H8 Hydrogen Mass Comparison
On the comparison of the mass of hydrogen in ethylene and propane
Now we want to know which of the two $C_2H_4 $and $C_3H_8 $has the higher mass of hydrogen.
First look at $C_2H_4 $, its molar mass is $M_ {C_2H_4} = (12\ times2 + 1\ times4) g/mol = 28g/mol $, where the mass fraction of hydrogen is $w_ {H1} =\ frac {1\ times4} {28} =\ frac {1} {7} $.
Looking at $C_3H_8 $again, its molar mass is $M_ {C_3H_8} = (12\ times3 + 1\ times8) g/mol = 44g/mol $, and the mass fraction of hydrogen is $w_ {H2} =\ frac {1\ times8} {44} =\ frac {2} {11} $.
To compare the size of $\ frac {1} {7} $and $\ frac {2} {11} $, the common score can be obtained: $\ frac {1} {7} =\ frac {11} {77} $, $\ frac {2} {11} =\ frac {14} {77} $.
Because $\ frac {11} {77} <\ frac {14} {77} $, that is, $w_ {H1} < w_ {H2} $.
It can be seen that $C_2H_4 $and $C_3H_8 $of the same mass, $C_3H_8 $contain higher mass of hydrogen.
Now we want to know which of the two $C_2H_4 $and $C_3H_8 $has the higher mass of hydrogen.
First look at $C_2H_4 $, its molar mass is $M_ {C_2H_4} = (12\ times2 + 1\ times4) g/mol = 28g/mol $, where the mass fraction of hydrogen is $w_ {H1} =\ frac {1\ times4} {28} =\ frac {1} {7} $.
Looking at $C_3H_8 $again, its molar mass is $M_ {C_3H_8} = (12\ times3 + 1\ times8) g/mol = 44g/mol $, and the mass fraction of hydrogen is $w_ {H2} =\ frac {1\ times8} {44} =\ frac {2} {11} $.
To compare the size of $\ frac {1} {7} $and $\ frac {2} {11} $, the common score can be obtained: $\ frac {1} {7} =\ frac {11} {77} $, $\ frac {2} {11} =\ frac {14} {77} $.
Because $\ frac {11} {77} <\ frac {14} {77} $, that is, $w_ {H1} < w_ {H2} $.
It can be seen that $C_2H_4 $and $C_3H_8 $of the same mass, $C_3H_8 $contain higher mass of hydrogen.

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