1. A substance that speeds up the rate of a chemical reaction without undergoing any change itself is known as a _______.   catalyst   nucleus   cation   counter ion   Hint Half-n-half Clue   2. Acids turn blue litmus paper _______.   pink   colorless   red   yellow   Half-n-half Clue   3. Fill in the missing word: Acid + _______ = Salt + Water   Non Metal   Metal   Oxygen   Base   Half-n-half Clue   4. Which of the following is not an allotrope of carbon?   Graphite   Silk   Charcoal   Diamond   Half-n-half Clue   5. Catalysts speed up the rate of chemical reactions.   True   False   6. The lead of a pencil mainly contains _______.   graphite   lead   carbon black   plastics   Half-n-half Clue   7. Which of the following is not a physical change?   Precipitation   Distillation   Oxidation   Decantation   Half-n-half Clue