Which of the
following is true of
matter during
chemical reactions?
during chemical reactions, some matter is
created and some matter is destroyed.
during chemical reactions, matter is neither
created nor destroyed; it just changes form.

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.

Which compounds have the empirical formula ch2o? a. c2h4o2 b. c3h6o3 c. ch2o2 d. c5h10o5 e. c6h12o6

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?