How to balance this equation:

Cu (s) + O2 (g) - - > CuO (s)

What happens to mass and energy in a closed system?

Which substance represents a compound? (1) C (s) (3) CO (g) (2) Co (s) (4) O2 (g)

The word weather is most commonly used to refer to the state of the atmosphere at a certain time. Why do you think the same word is used to refer to the breakdown of rocks?

Which statement is true for light passing into a medium that is more optically dense than the first medium through which it passed?

Jim poured Diethyl ether into a flask and taped a road flare to it. What would happen if he lit the flare and threw the flask?

Identify the spectator ions in the following complete ionic equation. 2k (aq) s2 - (aq) pb2 (aq) 2no-3 (aq) →pbs (s) 2k (aq) 2no-3 (aq) express your answers as ions separated by a comma.

4. A bird left its post and flew in a triangular path. It flew 21 yards south, 72 yards east and 75 yards diagonally to end back at the post. Is it a right triangle?

Condension occurs in the inside of your windows in Winters, why?

How can you use Hess's law to determine a reaction's enthalpy?

7. How much energy in KJ is released when 15.0 g of steam at 100.0 degrees Celsius is condensed and then frozen to ice at 0.0 degrees Celsius?