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. H2 and Fe represent _______.   elements   compounds   mixtures   Half-n-half Clue   3. Potassium sulfide solution is a _______ mixture.   heterogeneous   homogeneous   4. The constituents of a mixture do not retain their original properties.   True   False   5. A mixture of water and oil is _______ in nature.   homogeneous   heterogeneous   6. H2O and FeS represent _______.   mixtures   elements   compounds   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?   Atom   Molecule   Element   Mixture   Half-n-half Clue