What evidence indicates that a reaction has occurred? (Select all that apply.)

a. The temperature decreased.
b. A solid brown product formed.
c. The temperature increased.
d. A gas formed.
e. An explosion occurred.

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

Which statement is true about this reaction? 14n+1h 15o it is a practical source of energy on earth. it occurs only outside the solar system. its product is heavier than each of its reactants. it shows the critical mass of an element.

The molality of calcium chloride (cacl2) in an aqueous solution is 2.46 m. what is mole fraction of the solute?