9,000 meters
Because density is altered by altitude, the helium balloon can reach a height of 9,000 meters, or 29,537 feet. Anything higher than this altitude will cause the helium within the balloon to expand and the balloon to pop.
The reaction equation:
2H₂S + SO₂ → 3S + 2H₂O
Calculating moles of H₂S:
10 / 34 = 0.29
Moles of SO₂:
10 / 64 = 0.15
Stoichometric amounts of each reactant are present so the moles of S formed will be:
0.15 x 3 = 0.45
Mass of S formed = 14.4 grams
Heat because when substances react they produce heat.
1 mole is equal to 1 moles NaOH, or 39.99711 grams.
Hope this helped