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Moderate

Determining Equilibrium Concentrations

APCHEM-G4LLY5

Hydrogen gas reacts with gaseous carbon disulfide, producing methane gas and gaseous hydrogen sulfide. The equation for this reaction is:

$${ 4H }_{ 2 }(g)+C{ S }_{ 2 }(g)\rightleftharpoons C{ H }_{ 4 }(g)+2{ H }_{ 2 }S(g)$$

The table below shows all of the initial concentrations of the four gaseous species, along with one product concentration of methane gas.

Reactant or Product Initial Concentration (M) Equilibrium Concentration (M)
${ H }_{ 2 }(g)$ 0.50 ?
$C{ S }_{ 2 }(g)$ 0.30 ?
$C{ H }_{ 4 }(g)$ 0.30 0.25
${ H }_{ 2 }S(g)$ 0.40 ?

$\ $
Which of the following shows a CORRECTLY completed version of this table?

A
Reactant or Product Initial Concentration (M) Equilibrium Concentration (M)
${ H }_{ 2 }(g)$ 0.50 0.60
$C{ S }_{ 2 }(g)$ 0.30 0.35
$C{ H }_{ 4 }(g)$ 0.30 0.25
${ H }_{ 2 }S(g)$ 0.40 0.25
B
Reactant or Product Initial Concentration (M) Equilibrium Concentration (M)
${ H }_{ 2 }(g)$ 0.50 0.55
$C{ S }_{ 2 }(g)$ 0.30 0.35
$C{ H }_{ 4 }(g)$ 0.30 0.25
${H }_{ 2 }S(g)$ 0.40 0.35
C
Reactant or Product Initial Concentration (M) Equilibrium Concentration (M)
${ H }_{ 2 }(g)$ 0.50 0.70
$C{ S }_{ 2 }(g)$ 0.30 0.35
$C{ H }_{ 4 }(g)$ 0.30 0.25
${ H }_{ 2 }S(g)$ 0.40 0.30
D
Reactant or Product Initial Concentration (M) Equilibrium Concentration (M)
${ H }_{ 2 }(g)$ 0.50 0.40
$C{ S }_{ 2 }(g)$ 0.30 0.40
$C{ H }_{ 4 }(g)$ 0.30 0.25
${ H }_{ 2 }S(g)$ 0.40 0.25