Which statement correctly describes a physical change?

Molecules that contain nothing but hydrogen and carbon are

If a mixture of gases contained 78% nitrogen at a pressure of 984 torr and 22% carbon dioxide at 345 torr, what is the total pressure of the system?

What is the pH of a sample with [OH-] = 2.5 x 10-11 M?

What property of a molecule defines how it tastes?

The reaction pcl3 (g) + cl2 (g) ←-→pcl5 (g) has kp=0.0870 at 300 ∘c. a flask is charged with 0.50atmpcl3, 0.50atmcl2, and 0.20atmpcl5 at this temperature.

What is unique about the way that transition metals form compounds? a. They don't form compounds c. They can form bonds with the electrons in the two outer-most shells b. They are the most reactive d. They can donate all of their electrons

What prompted rutherford to do the alpha particle scattering experiment?

How many moles of hydrogen would be required to produce 5.0 mol of water?

What is the biggest difference between an exothermic and endothermic process? A. The direction of energy flow. B. The amount of energy transferred. C. The type of energy being transferred. D. The speed with which energy is transferred.

The mass of 1 mol of chromium (atomic mass 51.996 amu) is