Missing question: <span>Cr, Mn, Fe, Ba, Cu.
Answer is: Ba (barium).
Barium is metal from second group of periodic table of elements. Barium looses two electrons and has oxidation number +2.
Chromium has different oxidation numbers, usually +3 and +6, iron has oxidation numbers +2 and +3, copper +1 and +2 in their compounds.</span>
Answer is: <span>volume of balloon is </span>476,85 cm³.
density of air: d(air) = -0,0043 · 18,0°C + 1,2874.
d(air) = 1,21 kg/m³ = 1,21 · 10³/ 10⁶ = 0,00121 g/cm³.
m(balloon) = 0,577 g.
d(balloon) = d(air).
d(balloon) = m(balloon) ÷ V(balloon).
V(balloon) = m(balloon) ÷ d(balloon)
V(balloon) = 0,577 g ÷ 0,00121 g/cm³.
V(balloon) = 476,85 cm³.
We need to know the value of van't hoff factor.
The van't hoff factor is: 2.66 or 2.7 (approximately)
(NH₄)₂SO₄ is an ionic compound, so it dissociates in solution and produces 3 ionic species. Therefore van't hoff factor is more than one.
From the equation: Δ
=i
.m, where Δ
= elevation of boiling point=102.5 - 100=2.5°C.
m=molality of solute=1.83 m (Given)
= Ebullioscopic constant or Boiling point elevation constant= 0.512°C/m (Given)
i= Van't Hoff factor
So, 2.5= i X 0.512 X 1.83
i=
i=2.66= 2.7 (approx.)