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.
The thing that two changes have in common that snails growing shells and rust forming on a bicycle frame is option D. Both are caused by cooling.
<h3>How come snails develop shells?</h3>
Calcium carbonate is said to be the material that makes up the shell. The snail's shell expands as it grows to accommodate its growing body. Snails and slugs are also members of the mollusc family of creatures.
Therefore, note that air that has been mixed with the metal can make rust to develop. and as such, option D. Both are caused by cooling. is correct.
Learn more about snails growing shells from
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See full question below
What do these two changes have in common? snails growing shells rust forming on a bicycle frame Select all that apply.
A. Both are only physical changes.
B. Both are caused by heating.
C. Both are chemical changes.
D. Both are caused by cooling
Answer:
Option B.
Explanation:
As any reaction of combustion, the O₂ is a reactant and the products are CO₂ and H₂O. Combustion reaction for ethane is:
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
So 2 moles of ethane react with 7 moles of oxygen to make 4 moles of dioxide and 6 moles of water.
Then 2 moles of ethane will produce 4 moles of CO₂
<span>To solve this we assume that the gas inside the balloon is an ideal </span>gas. Then, we can use the ideal gas equation which is
expressed as PV = nRT. At a constant volume pressure and number of moles of the gas
the ratio of T and P is equal to some constant. At another set of condition, the constant is still the same. Calculations are as follows:
T1/P1 = T2/P2
P2 = T2 x P1 / T1
P2 = 25 x 29.4 / 75
P2 = 9.8 kPa
Explanation:
<u>Polar covalent bonding is the type of the chemical bond in which the pair of the electrons is unequally shared between the two atoms.</u> As a result, the atom with higher value of electronegativity acquires a slightly negative charge and the atom with lower value of electronegativity acquires a slightly positive charge.
In the molecule of 
, the bond which is closest to ionic end of bond spectrum is <u>N-H bond</u> because the nitrogen atom is more electronegative than hydrogen and is ionic in nature.
In the molecule of 
, the bond which is closest to ionic end of bond spectrum is <u>no one</u> because there is not much difference between carbon and hydrogen for the bond to be said as ionic.
In the molecule of 
, the bond which is closest to ionic end of bond spectrum is <u>O-H bond</u> because the oxygen atom is more electronegative than hydrogen and is ionic in nature.
