Answer:
C. spontaneous at all temperatures
Explanation:
The spontaneity of reaction is determined by the sign of the gibbs free energy.
A negative sign denotes that the reaction is spontaneous, positive sign means the reaction is not spontaneous.
From the question;
ΔS° = +253 J/K
ΔH° = -125 kJ/mol
ΔG = ΔH° - TΔS°
From the data given, the condition in which we can obtain a negative value of G, is at any value of T.
For any value of T, G would always be a negative value.
This means the correct option is option C.
Answer:
Explanation:
The net force on electron is electrostatic force between electron and proton in the nucleus .
Fc = 
This provides the centripetal force for the circular path of electron around the nucleus .
Centripetal force required = 
So
Answer:
12.99
Explanation:
<em>A chemist dissolves 716. mg of pure potassium hydroxide in enough water to make up 130. mL of solution. Calculate the pH of the solution. (The temperature of the solution is 25 °C.) Be sure your answer has the correct number of significant digits.</em>
Step 1: Given data
- Mass of KOH: 716. mg (0.716 g)
- Volume of the solution: 130. mL (0.130 L)
Step 2: Calculate the moles corresponding to 0.716 g of KOH
The molar mass of KOH is 56.11 g/mol.
0.716 g × 1 mol/56.11 g = 0.0128 mol
Step 3: Calculate the molar concentration of KOH
[KOH] = 0.0128 mol/0.130 L = 0.0985 M
Step 4: Write the ionization reaction of KOH
KOH(aq) ⇒ K⁺(aq) + OH⁻(aq)
The molar ratio of KOH to OH⁻is 1:1. Then, [OH⁻] = 0.0985 M
Step 5: Calculate the pOH
We will use the following expression.
pOH = -log [OH⁻] = -log 0.0985 = 1.01
Step 6: Calculate the pH
We will use the following expression.
pH + pOH = 14
pH = 14 - pOH = 14 -1.01 = 12.99
The cooling of a mint is just a sensation if you were to put mints into warm water the water would remain warm because it is just a cooling sensation. I hope this helps:)
Answer:
The pH of a solution of 0.00278 M of HClO₄ is 2.56
Explanation:
pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance and is calculated as:
pH= - log [H⁺]= - log [H₃O⁺]
On the other hand
, a Strong Acid is that acid that in an aqueous solution dissociates completely. In other words, a strong acid completely dissociates into hydrogen ions and anions in solution.
HClO₄ is a strong acid, so in aqueous solution it will be totally dissociated. Then, the concentration of protons is equal to the initial concentration of acid and the pH will be calculated:
pH= - log 0.00278
pH= 2.56
<u><em>The pH of a solution of 0.00278 M of HClO₄ is 2.56</em></u>
