Cobalt-60 can be used by scientists for the purpose of radioactive dating. cobalt-60 has a half-life of 5,272 years. a fossilized rock originally contained 25 grams of co-60. when tested, the rock only contains 6.25 grams of co-60. approximately how old is the item?

Which diagram shows the correct way to represent an ionic compound of magnesium oxide?

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.

28. which is not a reason that water is used to store spent fuel rods from nuclear power plants? water increases the speed of the chain reaction in the fuel rods. water protects nuclear power plant workers from the high temperature and radiation of the fuel rods. water acts as a radiation shield to reduce the radiation levels. water cools the spent rods. salts action