1. Which of the following is a compound?   Sodium sulfide   Sodium sulfide solution   Sodium   Hint Half-n-half Clue   2. Potassium sulfide solution is a _______ mixture.   heterogeneous   homogeneous   3. A mixture of water and oil is _______ in nature.   heterogeneous   homogeneous   4. 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   5. Which of the following is an element?   Calcium chloride solution   Calcium chloride   Calcium   Half-n-half Clue   6. H2 and Fe represent _______.   elements   compounds   mixtures   Half-n-half Clue   7. Copper sulfate solution can be further subdivided into simpler substances by physical (mechanical) means. Therefore, it is _______.   a mixture   an element   a compound   Half-n-half Clue