Question

What mass is associated with a $ 2 $ mole quantity of potassium dichromate?

Answer 1

Hint: Potassium dichromate is an inorganic compound with the molecular formula of $ {K_2}C{r_2}{O_7} $ . The number of moles of any compound is the ratio of the mass and molar mass of that compound. By substituting the moles and molar mass given the mass of potassium dichromate.
 $ n = \dfrac{w}{M} $
 $ n $ is number of moles
 $ w $ is mass of potassium dichromate
 $ M $ is the molar mass of potassium dichromate.

Complete answer:
Inorganic compounds are the compounds that were formed from the atoms other than carbon and hydrogen. The molecular formula of potassium dichromate is $ {K_2}C{r_2}{O_7} $ which consists of two potassium atoms, two chromium atoms, and seven oxygen atoms. From all these numbers of atoms and their molar masses based on the periodic table.
Molar mass of potassium atoms is $ 40gmo{l^{ - 1}} $ , two potassium atoms has $ 2 \times 40 = 80gmo{l^{ - 1}} $
Molar mass of chromium atoms is $ 52gmo{l^{ - 1}} $ , two chromium atoms has $ 2 \times 52 = 104gmo{l^{ - 1}} $
Molar mass of oxygen atom is $ 16gmo{l^{ - 1}} $ , seven oxygen atoms has $ 7 \times 16 = 112gmo{l^{ - 1}} $
Thus, the molar mass of potassium dichromate is $ 80 + 104 + 112 = 296gmo{l^{ - 1}} $
Given that potassium dichromate is associated with $ 2 $ moles
Substitute the moles, and molar mass in the above formula,
 $ 2mol = \dfrac{w}{{296gmo{l^{ - 1}}}} $
Thus, mass of potassium dichromate is $ 296 \times 2 = 592g $
 $ 592g $ of mass is associated with a $ 2 $ mole quantity of potassium dichromate.

Note:
Some atoms in the periodic table do not have the molar mass that is double to the atomic number. Thus, based on the periodic table only the molar mass of all the atoms in potassium dichromate should be calculated. Chromium and potassium molar masses are not equal to the double of the atomic number.