How long do balloons stay inflated with helium

Balloons last between 12-21 hours filled with helium

Explanation:

latex balloons generally last between 12-20 hours filled with helium, and about 2-3 days when treated with Hi-Float

a) 2KOH + NiSO₄ → Ni(OH)₂ + K₂SO₄

b) The precipitate that forms is Ni(OH)₂

c) We calculate the moles of each reagent:

0.1 L * 0.200 M KOH = 0.02 mol KOH

0.2 L * 0.150 M NiSO₄ = 0.03 mol NiSO₄

The amount of KOH needs to be twice the amount of NiSO₄, so for 0.03 mol NiSO₄ it would take 0.06 mol KOH. There are not as many, so KOH is the limiting reactant.

d) We calculate the amount of product formed using the limiting reactant:

0.02 mol KOH 1.8538 g Ni(OH)₂.

e) The final volume is 0.3 L

K⁺ ions did not react and remained in the solution:

[K⁺] = 0.02 mol / 0.3 L = 0.067 M

No OH⁻ ions remain in solution.SO₄⁻² ions did not react and remained in the solution

[SO₄⁻²] = 0.03 mol / 0.3 L = 0.100 M

The Ni⁺² moles that reacted were: 0.02 mol KOH * = 0.01 mol Ni⁺²

So the Ni⁺² moles that remained in solution are: 0.03-0.01 = 0.02 mol Ni⁺²

[Ni⁺²] = 0.02 mol / 0.3 L = 0.067 M