Question

You have 3L of a 2 molar magnesium chloride solution. How many moles of chloride ions are present?

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Answer 1

12 moles Cl⁻

Step-by-step explanation:

To find the moles Cl⁻, you need to (1) calculate the moles of magnesium chloride (MgCl₂) using the molarity equation and then (2) convert moles MgCl₂ to moles Cl⁻ (via the mole-to-mole ratio from formula subscripts). It is important to arrange the conversions in a way that allows for the cancellation of units.

Molarity (M) = moles / volume (L)

2 M = moles / 3 L

6 = moles MgCl₂

1 MgCl₂ = 1 Mg²⁺ and 2 Cl⁻

6 moles MgCl₂ 2 moles Cl⁻
------------------------ x ----------------------- = 12 moles Cl⁻
1 mole MgCl₂