Question

question
type the correct answer in the box. round your answer to the nearest whole number.
when oxygen reacts with hydrogen, it has the capacity to release 29 kilojoules of energy. inside a fuel cell, oxygen reacts with hydrogen to produce 23 kilojoules of useful energy. the rest of the energy is lost as heat. whats the efficiency percentage of the fuel cell?
the efficiency of the fuel cell is percent.

Explanation:

Step1: Recall efficiency formula

Efficiency = $\frac{\text{useful energy output}}{\text{total energy input}}\times100\%$

Step2: Identify values

Useful energy output = 23 kJ, total energy input = 29 kJ

Step3: Calculate efficiency

Efficiency = $\frac{23}{29}\times100\% \approx 79.31\%$

Step4: Round to nearest whole number

Rounding 79.31% gives 79%

Answer:

79