1. Objects appear to weigh less in water than air.   True   False   2. Hardness of water is caused by the presence of certain salts in it.   True   False   3. Water has maximum density at   0 oC   4 oC   32 oC   100 oC   Hint Half-n-half Clue   4. Earth is known as the blue planet because of the presence of   Water   Atmosphere   The continents   Sky   Half-n-half Clue   5. The process of conversion of water vapor to water on the surface of a cold glass tumbler is known as   Condensation   Evaporation   Boiling   Vaporization   Half-n-half Clue   6. What is the boiling point of water?   0 oC   32 oC   50 oC   100 oC   Half-n-half Clue   7. What is the melting point of ice?   0 oC   12 oC   32 oC   100 oC   Half-n-half Clue