The given compound is [tex] K_{2}Cr_{2}O_{7} [/tex]
Each formula unit of [tex] K_{2}Cr_{2}O_{7} [/tex] has 2 mol Potassium (K) atoms, 2 mol Chromium (Cr) atoms and 7 mol Oxygen (O) atoms.
Atomic weight of potassium is 39.0983 amu
Atomic weight of Chromium is 51.9961 amu
Atomic weight of Oxygen is 15.9994 amu.
Therefore the formula weight of [tex] K_{2}Cr_{2}O_{7} = [/tex]
[tex] 2 * 39.0983 amu + 2 * 51.9961 amu + 7 * 15.9994 amu [/tex]
= 294.1846 amu
