10. Which of the following is a way in which elements and compounds are similar?
A. Elements and compounds are both pure substances.
B. Elements and compounds are both listed on the periodic table.
C. Elements and compounds are both made up of different kinds of atoms.
D. Elements and compounds can both be broken down by physical changes
11. Why is water considered a pure substance?
A. Water can be broken down by physical means.
B. Water can be combined with other substances by physical means.
C. Each water molecule is identical.
D. Water molecules are made up of different types of atoms.
12. Which importance of elements in the human body is correctly paired?
A. Chlorine found outside the cells which serves as a major electrolyte.
B. Oxygen inside the cell essential in the conduction of nerve impulses.
C. Phosphorous is important in bones and teeth and some amino acids.
D. Sodium is important in nerve conduction and fluid balance.