Question

18. The mass of a quantity of NiCl2 is 24.6 g. How many formula units are in the sample?

Answer 1

its not A for sure becz i took the test i but b 1.9 3 1027 NiCl2 formula units

it was wrong answer

Answer 2

Answer is: A. 1.1 3 1023 NiCl2 formula units.

m(NiCl₂) = 24.6 g; mass of nickel(II) chloride.

M(NiCl₂) = 129.6 g/mol; molar mass of nickel(II) chloride.

n(NiCl₂) = m(NiCl₂) ÷ M(NiCl₂).

n(NiCl₂) = 24.6 g ÷ 129.6 g/mol.

n(NiCl₂) = 0.19 mol; amount of nickel(II) chloride.

Na = 6.022·10²³ 1/mol; Avogadro constant.

N(NiCl₂) = n(NiCl₂) · Na.

N(NiCl₂) = 0.19 mol · 6.022·10²³ 1/mol.

N(NiCl₂) = 1.13·10²³; number of formula units.