What is true about endothermic reactions? Endothermic reactions release heat to the surroundings.
The enthalpy of products in endothermic reactions is lower than the enthalpy of reactants.
The enthalpy of an endothermic reaction is positive.
Endothermic reactions have an enthalpy of zero.

Apiece of copper has a temperature of 75.6 0c. when the metal is placed in 100.0 grams of water at 19.1 0c, the temperature rises by 5.5 0c. what is the mass of the metal?

Americium-241 undergoes fission to produce three neutrons per fission event. if a neutron-absorbing material is mixed in with this sample so that the rate of neutron production drops down to 1.8 neutrons per fission event, which will be effective at achieving a critical mass? check all that apply. remove a deflective shield surrounding the sample. remove absorbent material mixed in with the sample. compress the sample of americium-241.

Which substance—wood or silver—is the better thermal conductor? a thermal conductor is a material that requires very little heat energy to change its temperature. explain your answer.