Nickel-63 is a radioactive element that decays to copper-63. Nickel-63 has a half-life of approximately 100 years. Vincent predicts that about 50 grams of a 200-gram sample of nickel-63 remains after 200 years. Is he correct? Why or why not? Explain.

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 of the following is not a true statement about dwarf planets? a the kuiper belt contains comets, asteroids, and dwarf planets. b ceres is a dwarf planet located in the kuiper belt. c the largest known dwarf planet in the solar system is named eris.

Ted and emily played a mixed doubles tennis match against jack and brenda. in the second match. ted and brenda played against jack and emily. which type of chemical reaction does the situation demonstrate?