How much energy is absorbed if 200 g of water at 60 C turns into steam at 140 C? You will need to know:
specific heat of water = 4.2 J/g*C
specific heat of steam = 2.1 J/g*C
heat of vaporization = 2,256 J

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

the population of unionid mussels in the hudson river decreased after zebra mussels were introduced. zebra mussels, a nonnative species, competed with the unionid mussels for food. the zebra mussels were able to outcompete the unionid mussels, allowing the zebra mussel population to increase dramatically over six years. the unionid mussel population decreased due to a lack of food.

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