1. Oxygen cannot be further subdivided into simpler substances by any physical or chemical means. Therefore, it is _______.   a mixture   an element   a compound   Hint Half-n-half Clue   2. Copper sulfate can be further subdivided into simpler substances by chemical means only. Therefore, it is _______.   a mixture   a compound   an element   Half-n-half Clue   3. Which of the following is a pure substance made up of one type of atoms?   Element   Compound   Mixture   Half-n-half Clue   4. Which of the following is a compound?   Sodium sulfide   Sodium   Sodium sulfide solution   Half-n-half Clue   5. Which of the following is a mixture?   Potassium carbonate   Potassium   Potassium carbonate solution   Half-n-half Clue   6. H2O and FeS represent _______.   compounds   mixtures   elements   Half-n-half Clue   7. Which of the following is the smallest part of a compound, whose properties are the same as those of the compound?   Mixture   Atom   Element   Molecule   Half-n-half Clue