Identify the atom below. he, he, be, or c

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Which element has the lowest electronegativity? calcium(ca) gallium(ga) selenium(se) bromine(br)

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?