## Chemistry: The Molecular Science (5th Edition)

The molarity of potassium dicromate is equal to $0.0159M$
1. Calculate the molar mass $(K_2Cr_2O_7)$: 39.1* 2 + 52* 2 + 16* 7 = 294.2g/mol 2. Calculate the number of moles $(K_2Cr_2O_7)$ $n(moles) = \frac{mass(g)}{mm(g/mol)}$ $n(moles) = \frac{ 2.335}{ 294.2}$ $n(moles) = 7.937\times 10^{- 3}$ 3. Find the concentration in mol/L $(K_2Cr_2O_7)$: 1000 ml = 1L 500 ml = 0.500L $C(mol/L) = \frac{n(moles)}{volume(L)}$ $C(mol/L) = \frac{ 7.937\times 10^{- 3}}{ 0.500}$ $C(mol/L) = 0.0159M$