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

20.4 L

imma come back to you hold on

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.