The law of conservation of matter states that matter is neither created nor destroyed in a chemical reaction. Which of the following must be true? * A the mass of the products is greater than the mass of the reactants
B the mass of the products is less than the mass of the reactants
C the mass of the reactants must equal the mass of the products

Alarge marble is dropped in a graduated cylinder with 35ml of water in it.the water level increases to 49ml.what is the volume of the marble

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

How do you identify the anode on a power source such as a battery? how do you identify the cathode? how are terms anion and cation?