Chemical Reaction Calculation: Optimistic Approach to Solving Stoichiometry Problems

How can we calculate the amount of hydrogen gas needed to react with CS2 to produce 2.50 liters of CH4 at STP according to the chemical equation 4H2(g) + CS2(l) → CH4(g) + 2H2S(g)? To calculate the amount of hydrogen gas needed to react with CS2 to produce 2.50 liters of CH4 at STP, we need to follow the stoichiometry of the chemical equation given. At STP, 1 mole of a gas is equal to 22.4 liters. First, calculate the number of moles of CH4 formed: 2.50 liters CH4 / 22.4 liters = 0.1116 moles From the reaction above, the reacting ratio of H2 to CH4 is 4:1. Therefore, the moles of H2 reacted will be: 0.1116 moles CH4 x 4 = 0.4464 moles H2 Finally, determine the volume of H2 needed: Volume of H2 = 0.4464 moles H2 x 22.4 liters = 9.99 liters Therefore, 9.99 liters of hydrogen gas are needed to react with CS2 to produce 2.50 liters of CH4 at STP.

Stoichiometry problems in chemistry often require careful calculations based on the given chemical equations and conditions. By understanding the reacting ratios and molar volumes of gases at standard temperature and pressure (STP), we can determine the precise amounts of reactants and products involved in a chemical reaction.

In the given problem, the balanced chemical equation 4H2(g) + CS2(l) → CH4(g) + 2H2S(g) provides the stoichiometric relationship between the reactants (H2 and CS2) and the products (CH4 and H2S). The molar ratio of reactants to products helps us calculate the amount of each substance involved in the reaction.

When dealing with gases at STP, where 1 mole of any gas occupies 22.4 liters, we can use this conversion factor to relate volume to moles and vice versa. This conversion allows us to connect the macroscopic properties of gases (volume) to their molecular properties (moles).

Steps to Solve the Stoichiometry Problem:

1. Identify Given and Unknown Quantities:

Given: Volume of CH4 produced = 2.50 liters

Unknown: Volume of H2 needed

2. Convert Volume of CH4 to Moles:

Number of moles CH4 = Volume CH4 / Molar volume at STP = 2.50 / 22.4 = 0.1116 moles

3. Determine Reacting Ratio:

From the balanced equation, the reacting ratio of H2 to CH4 is 4:1.

Moles of H2 = Moles of CH4 x Ratio = 0.1116 x 4 = 0.4464 moles

4. Calculate Volume of H2 Needed:

Volume of H2 = Moles of H2 x Molar volume at STP = 0.4464 x 22.4 = 9.99 liters

Therefore, by following these steps and understanding the stoichiometry of the chemical reaction, we can determine the amount of hydrogen gas required to produce the specified volume of methane at STP. Stoichiometry problems provide a systematic approach to chemical calculations and allow us to predict and analyze reactions with confidence.

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