Answer:
0.034 M is the molarity of sodium acetate needed.
Explanation:
The pH of the buffer solution is calculated by the Henderson-Hasselbalch equation:
![pH = pK_a + \log \frac{[A^-]}{[HA]}](https://tex.z-dn.net/?f=pH%20%3D%20pK_a%20%2B%20%5Clog%20%5Cfrac%7B%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
Where:
pK_a= Negative logarithm of the dissociation constant of a weak acid
![[Ac^-]](https://tex.z-dn.net/?f=%5BAc%5E-%5D)
= Concentration of the conjugate base
[HA] = Concentration of the weak acid
According to the question:
The desired pH of the buffer solution = pH = 5.27
The pKa of acetic acid = 4.74
The molarity of acetic acid solution = [HAc] = 0.01 M
The molarity of acetate ion =![[Ac^-] = ?](https://tex.z-dn.net/?f=%5BAc%5E-%5D%20%3D%20%3F)
Using Henderson-Hasselbalch equation:
![5.27= 4.74 + \log \frac{[Ac^-]}{[0.01 M]}](https://tex.z-dn.net/?f=5.27%3D%204.74%20%2B%20%5Clog%20%5Cfrac%7B%5BAc%5E-%5D%7D%7B%5B0.01%20M%5D%7D)
![[Ac^-]=0.0339 M\approx 0.034M](https://tex.z-dn.net/?f=%5BAc%5E-%5D%3D0.0339%20M%5Capprox%200.034M)
Sodium acetate dissociates into sodium ions and acetate ions when dissolved in water.
![[Ac^-]=[Na^+]=[NaAc]= 0.034M](https://tex.z-dn.net/?f=%5BAc%5E-%5D%3D%5BNa%5E%2B%5D%3D%5BNaAc%5D%3D%200.034M)
0.034 M is the molarity of sodium acetate needed.
Answer:
question 1- is B
question 2- is A
*I hope this helps you guys out!
Ecell = E°cell - RT/vF * lnQ
R is the gas constant: 8.3145 J/Kmol
T is the temperature in kelvin: 273.15K = 0°C, 25°C = 298.15K
v is the amount of electrons, which in your example seems to be six (I'm not totally sure)
F is the Faradays constant: 96485 J/Vmol (not sure about the mol)
Q is the concentration of products divided by the concentration of reactants, in which we ignore pure solids and liquids: [Mg2+]³ / [Fe3+]²
Standard conditions is 1 mol, at 298.15K and 1 atm
To find E°cell, you have to look up the reduction potensials of Fe3+ and Mg2+, and solve like this:
E°cell = cathode - anode
Cathode is where the reduction happens, so that would be the element that recieves electrons. Anode is where the oxidation happens, so that would be the element that donates electrons. In your example Fe3+ recieves electrons, and should be considered as cathode in the equation above.
When you have found E°cell, you can just solve with the numbers I gave you.
Atoms are made up of protons , electrons and neutrons ..,, Atoms of the same element with different number of neutrons are called isotopes. Saying that substance “contains only one type of atom “ really means that it contains only atoms that all have the same number of protons .
Answer:
the Molar heat of Combustion of diphenylacetylene 
= 
Explanation:
Given that:
mass of diphenylacetylene = 0.5297 g
Molar Mass of diphenylacetylene = 178.21 g/mol
Then number of moles of diphenylacetylene = 
= 
= 0.002972 mol
By applying the law of calorimeter;
Heat liberated by 0.002972 mole of diphenylacetylene = Heat absorbed by 
+ Heat absorbed by the calorimeter
Heat liberated by 0.002972 mole of diphenylacetylene = msΔT + cΔT
= 1369 g × 4.184 J g⁻¹°C⁻¹ × (26.05 - 22.95)°C + 916.9 J/°C (26.05 - 22.95)°C
= 17756.48 J + 2842.39 J
= 20598.87 J
Heat liberated by 0.002972 mole of diphenylacetylene = 20598.87 J
Heat liberated by 1 mole of diphenylacetylene will be = 
= 6930979.139 J/mol
= 6930.98 kJ/mol
Since heat is liberated ; Then, the Molar heat of Combustion of diphenylacetylene =
