Which ionic equation represents a spontaneous reaction that can occur in a voltaic cell? 1. cu(s) + zn(s) → cu2+(aq) + zn2+(aq) 2. cu(s) + zn2+(aq) → cu2+(aq) + zn(s) 3. cu2+(aq) + zn(s) → cu(s) + zn2+(aq) 4. cu2+(aq) + zn2+(aq) → cu(s) + zn(s)

How many grams of co(g) are there in 74.5 ml of the gas at 0.933 atm and 30o c?

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.

Suppose that some of the compound spilled out of the crucible after it was heated. would that cause the percent by mass of water in the compound determined by the experiment to be too low, too high, or unchanged? briefly explain your answer.