A compound contains 61.68% copper by mass. Calculate the molecular weight (molar mass) of this compound. (There are two atoms of copper in every formula unit of this compound.)
The molecular weight of the compound is_______g/mol
thanks
The molecular weight of the compound is_______g/mol
thanks
-
% Cu = mass Cu / mass of compound
Let x represent the atomic mass of the compound other than copper.
0.6168 = 2(63.5) / (2(63.5) + x)
0.6168 = 127 / (127 + x)
78.33 + 0.6168 x = 127
0.6168x = 48.67
x = 78.9
Molar mass = 127 + 78.9 = 205.9
This atomic mass is a very close match for a single selenium atom.
Let x represent the atomic mass of the compound other than copper.
0.6168 = 2(63.5) / (2(63.5) + x)
0.6168 = 127 / (127 + x)
78.33 + 0.6168 x = 127
0.6168x = 48.67
x = 78.9
Molar mass = 127 + 78.9 = 205.9
This atomic mass is a very close match for a single selenium atom.