Write net ionic equations for the reactions, if any, that occur when the aqueous solutions listed below are mixed. (Use the lowest possible coefficients. Include states-of-matter under SATP conditions in your answer. If there is no reaction, type "NONE" in the answer box.) (a) lead(II) nitrate and sodium chloride(b) silver nitrate and ammonium carbonate(c) lead(II) nitrate and sodium chloride(d) sodium phosphate and potassium nitrate(e) cobalt (III) chloride and sodium hydroxide

Which of the following happens during cell division? (a) energy is created (b) waste is eliminated (c) carbon dioxide is released (d) damaged cells are replaced

Which statement is usually true about the relationship between activation energy and reaction rates? low activation energy barriers result in low rates. high activation energy barriers result in low rates. low activation energy barriers result in no reaction. high activation energy barriers result in no reaction.

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.