How to find efficiency of a pulley system

Multiply the weight of the object by the distance it traveled to find the amount of work output. For the example: 10 lbs. x 1 foot = 10 foot-pounds. Find the work efficiency by dividing the work output by the work input and multiplying by 100.

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.

b is the correct answer

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