Melting butter is a physical change. Which best describes what is happening?
A. The butter changes into a different substance.
B. The butter contains a new arrangement of atoms.
C. The butter cannot turn into a solid again.
D. The butter no longer contains the same number of atoms.

The membrane surrounding a living cell consists of an inner and an outer wall that are separated by a small space. assume that the membrane acts like a parallel plate capacitor in which the effective charge density on the inner and outer walls has a magnitude of 7.0 × 10-6 c/m2. (a) what is the magnitude of the electric field within the cell membrane? (b) find the magnitude of the electric force that would be exerted on a potassium ion (k+; charge = +e) placed inside the membrane.

Holes drilled several kilometers into earth’s crust provide direct evidence about earth’s interior in the form of

Frank just graduated from eighth grade. assuming exactly four years from now he will graduate from high school how many seconds does he have until his high school graduation