Question

Suppose 1.87g of nickel(II) bromide is dissolved in 200.mL of a 52.0mM aqueous solution of potassium carbonate.

Answer 1

Answer:

0.0428 M

Explanation:

Because we're asked to calculate the molarity of nickel(II) cation, we need to determine all sources for that species, in this case, all Ni⁺² comes from the nickel(II) bromide solid (NiBr₂).

We use the molecular weight of NiBr₂ to calculate the moles of Ni:

1.87 g NiBr₂ ÷ 218.49g/mol * (1molNi⁺²/1molNiBr₂) =  8.55x10⁻³ mol Ni⁺²

Then we divide the moles by the volume in order to calculate the concentration:

8.55x10⁻³ mol Ni⁺² / 0.200 L = 0.0428 M