Answer:
H₂Se
Explanation:
A way of estimating the acidity of a weak acid is by analizing the<em> stability of the formed anion</em>. In this case, we should find a Group 6A element that in its anionic forms (HX⁻ and X⁻²) is more stable than HS⁻ and S⁻², thus it would be more acidic in aqueous solution.
The anionic forms of Se are more stable than the forms of S, similarly to how Br⁻ is more stable than Cl⁻.
In a way, all of the answers could be argued for (for example: in the first option: if the scientists' opinions are understood to be "informed understanding of the causes of events"), but one of the options is the best:
Scientific laws describe specific relationships in nature without offering
an explanation.
The reason why I think this is true is that many laws are phased too short and too concise to provide comprehensive explanations, instead they describe the relationships that must hold.
One of the options is pplain false:
Scientific laws explain why natural events occur. -"Scientific laws were theories that have been tested, proven, and adopted as laws." - since they are not adopted as laws.
Answer:
C. The conditions in which a substance exists in a certain phase.
Explanation:
Answer:
ΔH
°fCaO= -655.09 KJ/mol = ΔH
°fCaO
Explanation:
ΔH
°(reaction)a=ΔH
°f(product)-ΔH
°f(reactant)
where,
ΔH
°f(product)=is the standard heat of formation of products
-ΔH
°f(reactant)=is the standard heat of formation of reactants
The standard heat of formation of H
2
O
(
l
) is −
285.8
k
J
/
m
o
l
.
The standard heat of formation of Ca(OH
)2 is −
986.09
k
J
/
m
o
l
.
For the given reaction, the standard enthalpy change is calculated by the expression shown below.
ΔH
°(reaction)a=ΔH
°f(CaO+H2O)-ΔH
°f(Ca(OH)₂
65.2 = ΔH
°fCaO+( -265.8) -(-986.09)
= ΔH
°fCaO-265.8+986.09
65.2 = ΔH
°fCaO+ 720.29
65.2-720.29 = ΔH
°fCaO
-655.09 KJ/mol == ΔH
°fCaO
Yes, i believe that it can have a physical change but it is most likely chemical.
