1. Lime water turns milky after carbon dioxide is passed through it.   True   False   2. On burning charcoal which of the following gases is produced?   Oxygen   Hydrogen   Carbon Dioxide   Nitrous Oxide   Hint Half-n-half Clue   3. When we breathe which of the following gases do we use?   Helium   Hydrogen   Oxygen   Carbon Dioxide   Half-n-half Clue   4. Nitrogen constitutes nearly __ % of the atmosphere.   21   57   42   79   Half-n-half Clue   5. Which gas in the atmosphere saves us from the UV rays of the sun?   Oxygen   Ozone   Nitrogen   Carbon Monoxide   Half-n-half Clue   6. A barometer is used for measuring   Humidity   Atmospheric Pressure   Annual Rainfall   Temperature   Half-n-half Clue   7. Dry ice is   Ice with salt added   Solid Carbon Dioxide   Very Cold Ice   Any Frozen Liquid   Half-n-half Clue