He statement "matter can be neither created nor destroyed by chemical means, but it can be changed from one form to another" is the chemical law of

a. conservation of matter.
b. atomic disintegration.
(c.) conservation of energy.
d. definite proportions.

Which statements describe polyatomic ions? check all that apply. polyatomic ions have many charges. polyatomic ions have one overall charge. polyatomic ions repel other ions to form ionic bonds. polyatomic ions attract other ions to form ionic bonds. polyatomic ions are made up of only one type of atom. polyatomic ions are made up of two or more types of atoms.

Structure of the atoms: discovery of the nucleus in 1909i need answering all of these questions

Why is it important for scientists to review and repeat the work of other scientists? 1.a scientific theory must be tested three times before it is proven. 2.the scientific method only applies to repeated experiments. 3.an experiment may have had errors that the scientists didn't recognize. 4.the results of individual scientists may be influenced by bias. 5.an experiment must be performed twice before the data can be analyzed.