1. Which of the following gases is green in color?   Chlorine   Hydrogen   Neon   Krypton   Hint Half-n-half Clue   2. Which of the following is not a physical change?   Oxidation   Decantation   Precipitation   Distillation   Half-n-half Clue   3. A substance that absorbs moisture is called _______.   hydrophobic   amorphous   hydrophilic   hygroscopic   Half-n-half Clue   4. Which of the following is a chemical change?   Freezing of water   Boiling of water   Dissolving of salt in water   Rusting of iron   Half-n-half Clue   5. Which of the following is not an allotrope of carbon?   Diamond   Charcoal   Graphite   Silk   Half-n-half Clue   6. Catalysts speed up the rate of chemical reactions.   True   False   7. A pH below 7 indicates _______.   purity of the sample   alkalinity   presence of ions   acidity   Half-n-half Clue