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Korvikt [17]
2 years ago
10

A balloon filled with helium occupies 20.0 l at 1.50 atm and 25.0◦c. How many moles of helium will there be in the balloon at st

p?
Chemistry
1 answer:
satela [25.4K]2 years ago
8 0

Answer:

  • There will be 1.23 moles of helium in the balloon at STP

Explanation:

1) <u>Initial conditions of the helium gas</u>:

  • V = 20.0 liter
  • p = 1.50 atm
  • T = 25.0 °C = 25.0 + 273.15 K = 298.15 K

2) <u>Ideal gas equation</u>:

  • pV = n RT
  • p, V, and T are given above
  • R is the Universal constant = 0.0821 atm-liter / ( K - mol)
  • n is the unknown number of moles

3) <u>Solve for n</u>:

  • n = pV / (RT) =
  • n = 1.50 atm × 20.0 liter / (0.0821 atm-liter /k -mol ×298.15K)
  • n = 1.23 mol

4) <u>At STP:</u>

  • STP stands for standard pressure and temperature.
  • The amount (number of moles) of the gas will not change because the change of pressure and temperature, so the number of moles reamain the same: 1.23 mol.
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