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 would say B because c and d would decrease competition and a would do the same, or just kill the ecosystem.
Hope this helps and don't forget to hit that heart :)
Answer: The ionization of pure water forms <u><em>hydroxide and hydronium ions.</em></u>
Explanation:
Ionization is a reaction in the pure water in which water breaks down into its constituting ions that hydronium ion and hydroxide ions.
One molecule of water looses its proton to form hydroxide ion and l=the lost protons get associated with another water molecule to form hydronium ion.
solution:
Physical properties describe how a material looks. such as color, state of matter, shininess, Other physical properties include density, mp, bp, brittleness, malleability, conductivity, ductility, solubility in water. A physical property can be determined without changing the identity of the material.
Chemical properties describe how a material behaves.such as does it burn, does it corrode, does it react with air, does it react with water, does it act like a metal by giving away electrons o like a nonmetal by taking electrons, what type of bonds will it form, or is it inert, is it acidic or basic, Chemical properties can only be determined during a chemical reaction.
