If a substance begins with 64 atoms of radioisotope, how many will remain after two half-lives 

What are the spectator ions in 2h+ + so42- + ca2+ + 2r → caso4 + 2h+ + 21?

What is the temperature of 0.750 mol of a gas stored in a 6,850 ml cylinder at 2.21 atm? . 2.95 k 5.24 k 138 k 246 k

Pegmatites are igneous rocks in which the individual minerals are very large. typically, the minerals are all light-colored quartz, feldspar and muscovite. if you were given a black and white photograph of a pegmatite in a quarry (where the rock has been blasted and broken), what physical properties could you use to identify those three minerals in this hypothetical photo? describe each mineral and the specific diagnostic properties. be specific.