Analyze the reaction to determine whether the reaction is exothermic or endothermic. Explain your reasoning. A graph of time on the horizontal axis versus potential energy on the vertical axis for upper C upper H subscript 4 plus 2 upper O subscript 2 right arrow 2 upper H subscript 2 upper O plus upper C upper O subscript 2 plus 891 kilojoules. A line starts high on the vertical axis and runs parallel to the horizontal axis; this segment is labeled upper C upper H subscript 4 plus upper O subscript 2; the line rises, peaks, and falls sharply to near and parallel the horizontal axis. The parallel segment is labeled upper C upper O subscript 2 plus upper H subscript 2 upper O.