2 Which group of substances contains only compounds?
A C, O2, CH4,
B H, He, F
C CO2, CaCO3 , CH4
D F, Fe, He
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List four observations that indicate that a chemical reaction may be taking place

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?

Which of the following is not one of the steps in the scientific method a. hypothesize b. summarize c. analyze d. familiarize