Answer:
2)Both the salt dissolving and the evaporation of water are physical changes.
Explanation:
The two kinds of changes that has occurred are both physical changes.
Dissolution of a solute such as salt in water and evaporation of water from a solution are physical changes.
A physical change is one in which the physical property of matter is altered. Particularly the state and the form.
In many of these cases, the change is easily reversible.
Since this change is reversible in that we were able to collect the salt back, this is a physical change.
Answer:
c. ΔH° is positive and ΔS° is positive.
Explanation:
Hello,
In this case, as the Gibbs free energy for a reaction is defined in terms of the change in the enthalpy and entropy as shown below:
Thus, as the reaction becomes spontaneous (ΔG°<0) at temperatures above 1100K (high temperatures), it necessary that c. ΔH° is positive and ΔS° is positive as the entropy will drive the spontaneousness as it becomes smaller than TΔS°.
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Answer:
protists are part of the domain eukarya
protists make up the kingdom protista
hope this helps x
Molarity of acid=2.5M
pH=5.1.
ka=?
Now
We need to write an eqn to show the dissociation of the acid
HA + H2O === H3O+ + A-
Writing The Equilibrium(Or Acid dissociation constant) of this reaction
Ka =[H3O+] {A-]/ {HA].
The concept behind this is
concentration of Products divided by those of reactants. Water is not written because its a pure liquid and does not affect the Equilibrium constant.
Now If you have any Idea on ICE tables..
You'd know that the concentration of acid will decrease by 2.5-x
Whilst the products...will increase by x each
Note: This is when the ratio of their Moles are in 1:1
ka= x.x/2.5-x
Since the Moles of A- and H3O+ are in 1:1... Their concentrations at equilibrium will be the same
so
Ka= x²/2.5-x
Now what is x??
x is the Hydrozonium ion concentration.
we can get it from the pH formula
pH= -log (H3O+)
Making H3O+ subject by applying Logarithm Rules
H3O+ = 10^-ph
x=10^-5.1
=7.94x10^-6.
Now back to Ka
Ka= x²/2.5-x
Ka= (7.94x10^-6)²/2.5-(7.94x10^-6)
Ka= (7.94x10^-6)²/2.4999
Ka= 2.52x10^-11.
Was a Fun One
Answer:
C.
Fe goes from 0 to 2+, oxidation. It is reducing agent
N goes from 5+ to 2+, reduction. It is oxidizing agent
Explanation:
Oxidation number
Fe (s) has 0
FeSO4 has 2+
HNO3 N has 5+
NO N has 2+