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.
I believe the answer would be C, unbalanced.
Since the forces are in opposite directions, and aren't the same size, the answer would be unbalanced.
Latent heat of melting is the energy that a solid absorbs to change its phase as its liquid. During this process, since all energy is used to change the phase, the temperature is constant.
Here the latent energy of melting for 1 g of ice is 80 calories and that 1 g of ice only absorbed 60 calories. hence the phase is not changed because it requires more 20 calories to melt.
Hence 1 g of ice remains as its solid phase (ice).
The answer would be B, an electron because the proton is positive, neutron is neutral, and the nucleus is the center of the atom.