Copper has two naturally occurring isotopes. copper-63, with an atomic mass of 62.94 u, makes up 69.17 percent of the sample, and copper-65, with an atomic mass of 64.93 u, makes up the other 30.83 percent. calculate the weighted average atomic mass of copper based on the given information. give your answer in a total of four significant figures

In a sample of oxygen gas at room temperature, the average kinetic energy of all the balls stays constant. which postulate of kinetic molecular theory best explains how this is possible? a. attractive forces between gas particles are negligible because the particles of an ideal gas are moving so quickly. b. collisions between gas particles are elastic; there is no net gain or loss of kinetic energy. c. gases consist of a large number of small particles, with a lot of space between the particles. d. gas particles are in constant, random motion, and higher kinetic energy means faster movement.

Which produce would best increase the amount of heat energy that is actually gained by calorimeter b

Ibeg i need 20. a reaction produces 4.93 l of oxygen, but was supposed to produce 1 mol of oxygen. what is the percent yield?