Question

The graph below compares the rates of reaction of a burning candle and an exploding firework.

Comparing Chemical Reactions
A graph has time on the horizontal axis and concentration of reactants on the vertical axis. For an exploding firework, the concentration starts high, increases slightly and then decreases rapidly. For a burning candle the concentration starts high, increases more than the firework, and then decreases rapidly. The concentration for the burning candle is higher than the firework at all timepoints.

What can you conclude from the graph?
The reaction that causes a firework to explode requires less energy to start, and occurs more rapidly than the reaction that causes a candle to burn.
The reaction that causes a firework to explode requires less energy to start, and occurs less rapidly than the reaction that causes a candle to burn.
The reaction that causes a firework to explode requires more energy to start, and occurs less rapidly than the reaction that causes a candle to burn.
The reaction that causes a firework to explode requires more energy to start, and occurs more rapidly than the reaction that causes a candle to burn.

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Answer 1

This is an old question. I am answering to help out users who may be seeking out this question in the future.

notice how the x-axis is time. if the concentration reaches zero faster (more towards the left on the x-axis) the concentration of reactions decreases.

as for which one takes more energy... honestly I'm not 100% sure how to tell from the graph alone, but let's try to think about it qualitatively (how much energy is released by a flame vs. how much is released by a firework)