Cavendish prepared hydrogen in 1766 by the novel method of passing steam through a red-hot gun barrel: 4H2 O (g) 3Fe (s) ⟶ Fe3 O4 (s) 4H2 (g) What volume of H2 at a pressure of 745 torr and a temperature of 20 °C can be prepared from the reaction of 15. O g of H2 O?

Hey there!:

convert mass of H2O to mol, use given chemical equation to calculate moles of H2 produced, use ideal gas equation to calculate volume

convert mass of H2O to mol:

mol of H2O = mass / molar mass

= 15.0 / 18.0

= 0.833 mol

use given chemical equation to calculate moles of H2 produced

from given equation, 4 mol of H2 is formed from 4 mol of H2O

So,

moles of H2 = moles of H2O

= 0.833 mol

use ideal gas equation to calculate volume

use:

P*V = n*R*T

(745/760) atm * V = 0.833 mol * 0.0821 atm. L/mol. K * (20+273) K

0.9803 * V = 0.833 * 0.0821*293

V = 20.4 L

Answer: 20.4 L