Design a portable, 1-time-use hot pack or cold pack for treating injuries. The pack must have 100 g of water separated from a solid chemical and be activated only when the user does something to the pack to mix the 2 components. Your job is to determine how many grams of the chemical are required to achieve the following temperatures: hot pack, 55° C (131° F); cold pack, 3° C (37° F).

What are the measurements I can use to obtain 55° C (131° F) for the hot pack, and 3° C (37° F) for the cold pack? What chemicals should I use for each?

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.