28:20 What is Avogadro’s number?
the number of atoms in exactly 14.00 g of carbon-12
the number of atoms in a kilogram of any substance
the number of atoms, molecules, ions, formula units, or other particles in a mole of a substance
the number of atoms, molecules, ions, formula units, or other particles in a gram of a substance

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy