How many grams are in 3.8 m moles of $CH_4$ ?

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Answer 1 · 2015-12-06T19:28:21

One mole of methane has a mass of 16.0 g.

In $3.80$ $mmol$ , there are $3.80$ $xx10^(-3)$ $cancel(mol)$ $xx$ $16.0*g*cancel(mol^-1)$ $=$ $??$ $g$ .

Answer 2 · 2015-12-06T19:57:41

$"3.8 mmol CH"_4"$ has a mass of $"0.061 g"$ .

The molar mass (mass of one mole) of $"CH"_4"$ $=$ $(1xx12.0107"g/mol")+(4xx1.00794"g/mol")="16.04246 g/mol"$

Convert 3.8 mmol to mol.

$3.8cancel"mmol"xx(1"mol")/(1000cancel"mmol")="0.0038 mol"$

Multiply moles times molar mass.

$0.0038cancel"mol CH"_4xx(16.04246"g CH"_4)/(1cancel"mol CH"_4)="0.061 g CH"_4"$ (rounded to two significant figures)

How many grams are in 3.8 m moles of CH_4CH_4?