What is the rate of formation of C2H4 between 20 and 30 seconds for the reaction: C4H8(g) → 2 C2H4(g), given the tabulated data collected for the concentration of C4H8 as a function of time?

Verified step by step guidance

1. Identify the reaction: \( \text{C}_4\text{H}_8(g) \rightarrow 2 \text{C}_2\text{H}_4(g) \).
2. Understand that the rate of formation of \( \text{C}_2\text{H}_4 \) is related to the rate of disappearance of \( \text{C}_4\text{H}_8 \).
3. Use the rate expression: \( \text{Rate of formation of } \text{C}_2\text{H}_4 = -2 \times \frac{\Delta [\text{C}_4\text{H}_8]}{\Delta t} \).
4. Determine \( \Delta [\text{C}_4\text{H}_8] \) by finding the change in concentration of \( \text{C}_4\text{H}_8 \) between 20 and 30 seconds from the data.
5. Calculate \( \Delta t \) as the difference in time, which is 30 seconds - 20 seconds.

Key Concepts

Rate of Reaction

The rate of reaction refers to the change in concentration of reactants or products over time. It is typically expressed in terms of molarity per second (M/s). Understanding how to calculate the rate of formation of a product, such as C2H4, involves determining the change in its concentration over a specified time interval.

Stoichiometry

Stoichiometry is the relationship between the quantities of reactants and products in a chemical reaction, based on the balanced chemical equation. In the reaction C4H8(g) → 2 C2H4(g), the stoichiometric coefficients indicate that for every mole of C4H8 consumed, two moles of C2H4 are produced. This relationship is crucial for calculating the rate of formation of C2H4 from the change in concentration of C4H8.

Concentration vs. Time Data

Concentration vs. time data provides a quantitative measure of how the concentration of a substance changes over a specific period. In this context, analyzing the tabulated data for C4H8 allows for the determination of its concentration at different times, which is essential for calculating the rate of formation of C2H4 between 20 and 30 seconds.