Estimate the number of atoms/cm² in a beryllium (100% 9Be) foil that is 3 mm thick

Which best represents the law of conservation of mass ?

The california mussel (mytilus californianus) attaches itself to a rock or other solid surface with a bundle of filaments known as the byssus. imagine that 15.0 j of work is done to stretch the distal end of the byssus. it releases 10.8 j of thermal energy as it relaxes. what is the resilience of the distal end of the byssus?

When using the scientist method, which step comes last?