2. A 0.45g sample of mineral ore is analyzed for chromium and found to contain 0.560mg Cr2O3. Express the concentration of Cr2O3 in the sample as:
(a) Percent (%)
(b) Parts per thousand (ppt)
(c) Parts per million (ppm)
(d) Parts per billion (ppb)​

Your roll: experienced electron speech is adressed to: a new "freshman class" of electrons job: write a speech task: you are to pretend that you are giving a speech to a new group of electrons. be sure to mention their placement in an atom, their charge, and their role in chemical bonding (ionic and covalent) be specific!

Both 1,2−dihydronaphthalene and 1,4−dihydronaphthalene may be selectively hydrogenated to 1,2,3,4−tetrahydronaphthalene. one of these isomers has a heat of hydrogenation of 101 kj/mol (24.1 kcal/mol), and the heat of hydrogenation of the other is 113 kj/mol (27.1 kcal/mol). match the heat of hydrogenation with the appropriate dihydronaphthalene.

Fission of uranium-235 products energy and a. isotopes of smaller elements b. isotopes of larger elements c. lighter isotopes of uranium d. heavier isotopes of uranium