The nuclide nb decays by beta emission with a half-life of 1.23 hours. the mass of a 97nb atom is 96.908 u. (a) how many grams of "'nb are in a sample that has a decay rate from that nuclide of 456 sl? (b) after 5.04 hours, how many grams of %7nb remain?

An unknown substance is a white solid at room temperature and has a melting point of 78 °c. which of the following substances is most likely to be the identity of the unknown sample? a. naphthalene, a molecular solid with the formula c10h8 b. silica, a network solid held together by covalent bonds with the formula sio2 c. calcium chloride, an ionic compound with the formula cacl2 d. water, an molecular compound with the formula h2o