Calculate the average atomic mas of an unknown element that has two naturally-occurring isotopes.

the first isotope occurs 75.47% of the time and has a mass of 248.7 a. m.u.
the second isotope occurs 24.53% of the time and has a mass of 249.4 a. m.u.

Which of the following happens during cell division? (a) energy is created (b) waste is eliminated (c) carbon dioxide is released (d) damaged cells are replaced

The sum of the oxidation numbers in a neutral compound is always

In november 1987, a massive iceberg broke loose from the antartic ice mass and floated free in the ocean. the chunk of ice was estimated to be 98 mi long, 25 mi wide, and 750 ft thick. a typical backyard swimming pool contains about 24,000 gallons of water. how many of these pools could you fill from the water in this iceberg? (assume the iceberg is a rectangular solid of the above dimensions and consists of water only). express answer in scientific notation.