Standard Temperature and Pressure Video Lessons

Concept: Standard Temperature and Pressure

# Problem: Hydrogen gas (a potential future fuel) can be formed by the reaction of methane with water according to the following equation:CH4(g) + H2O(g) → CO(g) + 3 H2 (g)In a particular reaction, 26.0 L of methane gas (measured at a pressure of 734 torr and a temperature of 25 oC) is mixed with 22.6 L of water vapor (measured at a pressure of 704 torr and a temperature of 125 oC). The reaction produces 26.6 L of hydrogen gas measured at STP.What is the percent yield of the reaction?

###### FREE Expert Solution

CH4(g) + H2O(g) → CO(g) + 3 H2 (g)

Calculate how much H2(g) is produced from each reactant:

$\overline{)\mathbf{PV}\mathbf{=}\mathbf{nRT}}\phantom{\rule{0ex}{0ex}}\mathbf{n}\mathbf{=}\frac{\mathbf{PV}}{\mathbf{RT}}$

H2(g) from CH4(g):

P = 0.9658 atm

V = 26.0 L
T = 25°C + 273.15 = 298.15 K

nCH4 = 1.0263 mol

moles H2 = 3.079 mol

H2(g) from H2O(g):

22.6 L of water vapor (measured at a pressure of 704 torr and a temperature of 125 oC

P = 0.9263 atm

V = 22.6 L
T = 125°C + 273.15 = 398.15 K

nH2O = 0.6407 mol

moles H2 = 1.922 mol

H2O(g): produces a smaller amount of H2(g) → H2O(g) is the limiting reactant

theoretical yield = 1.922 mol H2

Calculate the theoretical yield of H2(g) (volume):

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###### Problem Details

Hydrogen gas (a potential future fuel) can be formed by the reaction of methane with water according to the following equation:
CH4(g) + H2O(g) → CO(g) + 3 H2 (g)
In a particular reaction, 26.0 L of methane gas (measured at a pressure of 734 torr and a temperature of 25 oC) is mixed with 22.6 L of water vapor (measured at a pressure of 704 torr and a temperature of 125 oC). The reaction produces 26.6 L of hydrogen gas measured at STP.

What is the percent yield of the reaction?