Question

question 2:
methane gas (ch₄), reacts with gaseous water to form carbon monoxide gas and hydrogen gas.
how many liters of hydrogen gas are theoretically formed if 300. l of methane gas (ch₄) react with 250. l of gaseous water at stp?
a. 300. b. 250. c. 600. d. 500. e. 750.

Explanation:

Step1: Write the balanced chemical equation

$$\mathrm{CH_4(g) + H_2O(g) ightarrow CO(g)+3H_2(g)}$$

At STP, the volume ratio of gases is equal to the mole ratio (Avogadro's law: \(V = n\times V_m\), \(V_m\) is constant at STP).

Step2: Determine the limiting reactant

From the balanced equation, the ratio of \(V(\mathrm{CH_4}):V(\mathrm{H_2O}) = 1:1\).
We have \(V(\mathrm{CH_4})=300\space L\) and \(V(\mathrm{H_2O}) = 250\space L\).
Since \(250<300\), \(\mathrm{H_2O}\) is the limiting reactant.

Step3: Calculate the volume of \(H_2\)

Using the ratio \(V(\mathrm{H_2O}):V(\mathrm{H_2})=1:3\) (from the balanced equation).
If \(V(\mathrm{H_2O}) = 250\space L\), then \(V(\mathrm{H_2})=3\times V(\mathrm{H_2O})\)
\(V(\mathrm{H_2})=3\times250\space L = 750\space L\)

Answer:

E. 750.