Download Prep 2 science guide answer part 3

Prep. 2 revision sheet guide answers ( part 3 )
Science
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A ) 1- Transition elements
2- Neutrons
3- Positive ions ( Cations )
4- Polar compounds
5- Cesium
6- Non-metals
----------------------------------------------------------------------B ) 1- basic , acidic
2- atmospheric , atmospheric air
3- Cobalt 60 , gamma rays
4- 3km , 90 %
------------------------------------------------------------------------------C) How you can differentiate between two pieces of sodium and silver.
By reacting both of them with water :
 Sodium reacts with water giving alkai solution ( NaOH ) and hydrogen gas
evolves that burn with a pop sound .
2Na + H2O
2NaOH + H2
 While silver doesn’t react with water .
Ag + H2O
No reaction
------------------------------------------------------D) Give three examples of the most dangerous pollutants of ozone layers
 Chloroflourocarbon CFC known as freons ( CFCl3 )
 Halons ( Used in fire extinguisher )
 Methyl bromide ( used in insecticide industry )
 Nitrous oxide ( the exhaust of ultrasonic airoplanes ( Concorde )
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A)
1-Thermosphere
2- Charged ions
3 -Wireless communications and broadcasting
4- Van Allen belts
-------------------------------------------------------B )
C )
1-Altitude above sea level
3Km
9Km
11Km
13Km
2-Temperature at this height
5C
-34C
-47C
-60C
3- Atmospheric pressure
732mb 323mb 251mb 100mb
12-
Na + Br2
Br2 + KI
3-
2Na + H2O
2NaBr ( Sodium bromide )
2KBr + I2
2NaOH + H2