A student places a block of hot metal into a coffee cup calorimeter containing 162.9 g of water. The water temperature rises from 23.7 °C to 35.3 °C. how much heat did the water absorb and how much heat did the metal lose

answerleaving cheese out to get moldy;

you need to stop taking that class

it is the minimum amount of material needed to sustain a fission reaction.

critical mass is the minimum amount of fissionable material that must be assembled for a sustained fission reaction to take place. although two to three neutrons are produced for every fission, not all of these neutrons are available for continuing the fission reaction. if the conditions are such that the neutrons are lost at a faster rate than they are formed by fission, the chain reaction will not be self-sustaining.   at the point where the chain reaction can become self-sustaining, this is referred to as critical mass.