The energy that leaves or enters a system during a chemical reaction comes from what source *
The building and breaking of chemical bonds
the conversion of mass to energy
Heat absorbed by the surroundings
The kinetic energy or electron motion
Which of the following the best definition for the word Kinetic Energy?
2 points

If 90.0 grams of ethane reacted with excess chlorine,how many grams of dicarbon hexachloride would form

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

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?