When an apple is cut, it often turns brown. What does the color chan indicate? OA) physical change only
OB) chemical change only
OC) physical and chemical changes

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.

Predict whether the changes in enthalpy, entropy, and free energy will be positive or negative for the boiling of water, and explain your predictions. how does temperature affect the spontaneity of this process?

The polymer used for the nonstick surface of cooking utensils is 24.0%c and 76%f by mass. what is the empirical formula of this polymer?