Question #f0d05
1 Answer
Explanation:
My guess here would be that you already have the empirical formula of tartaric acid, and that you must find its molecular formula by using its molar mass.
Assuming that the starting point here is the empirical formula of tartaric acid looks like this
#"C"_2"H"_3"O"_3 -># empirical formula
Now, a compound's empirical formula tells you the smallest whole number ratio that exists between the atoms of its constituent elements.
In this case, you know that the molecular formula, which tells you the exact number of atoms that make up a molecule of said compound, will contain
#color(black)("2 atoms of C" color(red)(" for every ") {("3 atoms of H"),("3 atoms of O") :}#
In essence, you're looking for a multiple of the empirical formula.
Tartaric acid is said to have a molar mass of
In this case, you will have
#2 xx "12.011 g mol"^(-1) " "color(blue)(+)#
#3 xx "1.00794 g mol"^(-1)#
#3 xx "15.9994 g mol"^(-1)#
#color(white)(aaaaaaaaaaaaaaaaaa)/color(white)(aaaaaaaaaaaaaaaaa)#
#"75.044 g mol"^(-1) -> # the molar mass of the empirical formula
So, if the empirical formula has a molar mass of
#(150 color(red)(cancel(color(black)("g mol"^(-1)))))/(75.044color(red)(cancel(color(black)("g mol"^(-1))))) = 1.999 ~~ color(red)(2)#
to get the molecular formula. This means that the molecular formula of tartaric acid will be
#("C"_2"H"_3"O"_3)_color(red)(2) implies color(green)(|bar(ul(color(white)(a/a)"C"_4"H"_6"O"_6color(white)(a/a)|)))#
Here's how a molecule of tartaric acid looks like
