The amount of heat required to melt 2 lbs of ice is twice the amount of heat required to melt 1 ib of ice. is this observation a macroscopic or microscopic description of chemical behavior? explain your answer.

This is a macroscopic observation.

Explanation:

When you have something that It is depend on the mass, you can be sure that this is a macroscopie description of chemical behavior, because macroscopie observation can be measured with the extensive magnitudes such as volume, mass and lenght.

The answer is; B

This is because enriched uranium has minimal impurities. Therefore, the uranium-235 atoms are concentrates together and the chances that the neutron will bombard another U-235 atom in the vicinity is high. This increases the rate of radioactive a chain reaction. This is why enriched uranium is used to make  nuclear bombs and nuclear reactors.