1. A substance that absorbs moisture is called _______.   hydrophobic   hygroscopic   hydrophilic   amorphous   Hint Half-n-half Clue   2. A pH below 7 indicates _______.   purity of the sample   acidity   presence of ions   alkalinity   Half-n-half Clue   3. A substance that speeds up the rate of a chemical reaction without undergoing any change itself is known as a _______.   nucleus   catalyst   cation   counter ion   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. Solubility of a substance in a solvent usually increases with an increase in temperature.   True   False   6. The 'fizz' in soft drinks is caused by _______.   nitrogen   hydrogen   Carbon dioxide   helium   Half-n-half Clue   7. Catalysts speed up the rate of chemical reactions.   True   False