1. The 'fizz' in soft drinks is caused by _______.   helium   nitrogen   Carbon dioxide   hydrogen   Hint Half-n-half Clue   2. Solubility of a substance in a solvent usually increases with an increase in temperature.   True   False   3. What is the combination of any substance with oxygen known as?   Oxidation   Reduction   Combustion   Hydrogenation   Half-n-half Clue   4. The two allotropes of phosphorus are _______ and _______.   Red, Yellow   Crystalline, Amorphous   Alpha, Beta   Rhombic, Monoclinic   Half-n-half Clue   5. A substance that speeds up the rate of a chemical reaction without undergoing any change itself is known as a _______.   counter ion   nucleus   cation   catalyst   Half-n-half Clue   6. Which of the following gases is green in color?   Krypton   Chlorine   Neon   Hydrogen   Half-n-half Clue   7. What gas is evolved when dilute sulfuric acid is added to zinc?   Sulfur Dioxide   Argon   Hydrogen   Hydrogen Peroxide   Half-n-half Clue