Which of these statements is true?
a. some molecules may contain no atoms.
b. some elements found in nature exist as molecules.
c. some compounds include only one type of element.
d. some atoms are made of two or more different elements.

Your roll: experienced electron speech is adressed to: a new "freshman class" of electrons job: write a speech task: you are to pretend that you are giving a speech to a new group of electrons. be sure to mention their placement in an atom, their charge, and their role in chemical bonding (ionic and covalent) be specific!

Write the empirical chemical formula of calcium with a mass percent of 38.8, phosphorus with a mass percent of 20.0, and oxygen with a mass percent of 41.3.

What effect does a decrease in temperature have on the overall rate of a chemical reaction? a decrease in temperature decreases . the reaction rate will