Table of contents

5. Molecules and Compounds

Calculating Molar Mass

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Multiple Choice

The reaction between nickel metal and hydrochloric acid is not a simple dissolution. The product formed is NiCl₂ • 6 H₂O (s), nickel (II) chloride hexahydrate, which has exactly 6 waters of hydration in the crystal lattice for every nickel ion. What is the molar mass of nickel (II) chloride hexahydrate, NiCl₂ • 6 H₂O (s)?

228.99 g/mol

231.01 g/mol

234.71 g/mol

237.69 g/mol

Verified step by step guidance

Identify the chemical formula for nickel (II) chloride hexahydrate: NiCl2 • 6 H2O.

Determine the atomic masses of each element involved: Nickel (Ni), Chlorine (Cl), Hydrogen (H), and Oxygen (O). Use the periodic table for reference.

Calculate the molar mass of NiCl2 by adding the atomic mass of nickel and twice the atomic mass of chlorine: M(NiCl2) = M(Ni) + 2 * M(Cl).

Calculate the molar mass of 6 water molecules (6 H2O) by adding the atomic masses of hydrogen and oxygen: M(6 H2O) = 6 * (2 * M(H) + M(O)).

Add the molar mass of NiCl2 and 6 H2O to find the total molar mass of nickel (II) chloride hexahydrate: M(NiCl2 • 6 H2O) = M(NiCl2) + M(6 H2O).

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