Answer: 


Explanation:
Entropy is the measure of randomness or disorder of a system.
A system has positive value of entropy if the disorder increases and a system has negative value of entropy if the disorder decreases.
1. 
As 4 moles of gaseous reactants are changing to 2 moles of gaseous products, the randomness is decreasing and the entropy is negative
2. 
As 9 moles of gaseous reactants are changing to 10 moles of gaseous products, the randomness is increasing and the entropy is positive.
3. 
As 1 mole of solid reactants is changing to 2 moles of gaseous products, the randomness is increasing and the entropy is positive.
4. 
As 4 moles of gaseous reactants is changing to 5 moles of gaseous products, the randomness is increasing and the entropy is positive
5. 
As 4 moles of gaseous reactants is changing to 1 moles of gaseous products, the randomness is decreasing and the entropy is negative.
Answer:
Waves carry energy from place to place.
Explanation:
Some waves are used for mainly communication and phone signals. They help people get internet in the middle of nowhere if you are near an energy wave.
Answer:
Oxidation state shows the total number of electrons which have been removed from an element (a positive oxidation state) or added to an element (a negative oxidation state) to get to its present state