When radioactive uranium decays to produce thorium, it also emits a particle. as seen in the balanced nuclear equation, this particle can best be described as

a) a helium atom.
b) an alpha particle or a helium atom.
c) a beta particle or a hydrogen nucleus.
d) an alpha particle or a helium nucleus.

Silica, sio2, is formed on silicon as an electrically insulating layer for microelectronic devices. silica is formed when silicon is exposed to o2 gas at an elevated temperature. at 900˚c, it takes 90 minutes for the oxygen to diffuse from the surface to form a 0.06 micron (0.06 x 10-6 m) thick layer of sio2 on

Ican determine the molar mass of an element by looking on the under the atomic mass for the element. for example the molar mass of phosphorus is 30.974 grams/mole. avogadro’s number tells me the amount of representative particles in 1 mole of any substance. this means 12.011 gram sample of carbon and a 32.0 gram sample of sulfur have the same number of atoms.

The decimals you found in part b are called repeating decimals. in the gizmo, repeating decimals are rounded to two places. how does the gizmo show you that a decimal has been rounded?