Question

How many moles are in 12.64 grams of carbon dioxide?

Answer 1

There are `"0.2872 mol CO"_2"` in `"12.64 g CO"_2`.

Explanation:

Divide the given mass of `"CO"_2` by its molar mass `(M)`. The molar mass of `"CO"_2` is determined by multiplying the subscript of each element by its molar mass and adding them. The molar mass of an element is its atomic weight on the periodic table in g/mol.

`M_("CO"_2")` `=` `(1xx"12.011 g/mol C")+(2xx"15.999 g/mol O")="44.009 g/mol"`

Since molar mass is a fraction `("g"/"mol")`, we can divide by multiplying by the reciprocal of the molar mass `("mol"/"g")`.

`12.64color(red)cancel(color(black)("g CO"_2))xx(1"mol CO"_2)/(44.009color(red)cancel(color(black)("g CO"_2)))="0.2872 mol CO"_2`