Bromine boils at 59ºC is this a physical or chemical change?

Some people think that hydroelectric and solar power should be used to supply all of the electricity for the Unite States. Which of the following would be a flaw in this plan?

What happens as blood passes through the capillaries in the small intestine

1. What is the density of a rock that has a mass of 243 g and a volume of 7.9 cm3?

How do you know if energy is endothermic or exothermic?

What is Rubisco and its relationship to photosynthesis?

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?