1- If 154.0 grams of potassium metal reacts with excess water, then how many grams of
potassium hydroxide and hydrogen gas are formed? What volume of hydrogen gas, in liters, is formed at STP? Be sure to balance the reaction first.
___K(s) + ____H2O(l) → ____KOH(aq) + ____H2(g)

2- The burning of solid sulfur in air produces sulfur dioxide gas.
S + O2 → SO2
Balance the reaction. How many moles of sulfur dioxide does the burning of 3 moles of sulfur form? Calculate the volume of sulfur dioxide produced at STP.

Relax

Respuesta :

So

  • 4K+4H_2O—⟩4KOH+2H_2

Moles of Potassium

  • 154/39
  • 3.9mol

See molar ratio is same for K,KOH,H_2O i.e 4 .

  • So same moles of all

Mass of Water

  • 3.9(18)
  • 70.2g

Mass of KOH

  • 56(3.9)
  • 218.4g

#2

  • S+O_2—»SO_2

Balanced already

3 mols of S form 3 mol SO_2

At STP 1mol=22.4L

  • Volume=22.4(3)=67.2L