Which of the following can be true about a chemical reaction

a chemical reactions can release heat <
b chemical reactions can take in heat
c chemical reactions can create new products
d chemical reactions never require energy

The length of a vector arrow represents its magnitude and the point represents its direction true or false apex

Which theory was contradicted by experiments with the photoelectric effect? light spreads out after it passes through a small opening. as soon as light strikes metal, electrons will be ejected. visible light, regardless of color, will cause the ejection of electrons when striking metal. the kinetic energy of ejected electrons depends on the frequency of light that strikes the metal.

Nan element’s square on the periodic table, the number with the greatest numerical value represents the