Oil and fat containing food items are flushed with nitrogen. Why ?
Nitrogen is an inert gas and does not easily react with these substances. On the other hand, oxygen reacts with food substances and makes them rancid. Thus, bags used in packing food items are flushed with nitrogen gas to remove oxygen inside the pack. When oxygen is not present inside the pack, rancidity of oil and fat containing food items is avoided.
Identify the substances that are oxidised and the substances that are reduced in the following reactions.
$(i)$ $4 Na ( s )+ O _{2}( g ) \rightarrow 2 Na _{2} O ( s )$
$(ii)$ $CuO ( s )+ H _{2}( g ) \rightarrow Cu ( s )+ H _{2} O ( l )$
What does one mean by exothermic and endothermic reactions ? Give examples.
Why is the amount of gas collected in one of the test tubes in image double of the amount collected in the other ? Name this gas.
Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.
Explain the ''Rancidity'' terms with one example.