We can solve this without a concrete formula through dimensional analysis. This works by manipulating the units such that you end up with the unit of the final answer. Manipulate them by cancelling units that appear both in the numerator and denominator side. As a result, we must be left with the units of g. The current in A or amperes is equivalent to amount of Coulombs per second. Since this involves Coulombs, we will use the Faraday's constant which is 96,500 C/mol electron. The reaction is:
Cr³⁺(aq) + 3e⁻ --> Cr(s)
This means that for every 3 moles of electron transferred, 1 mole of Chromium metal is plated. The molar mass of Cr: 52 g/mol. The solution is as follows:
Mass of Chromium metal = (8 C/s)(60 s/1 min)(160 min)(1 mol e⁻/96,500 C)(1 mol Cr/3 mol e)(52 g/mol)
<em>Mass of Chromium metal = 13.79 g</em>
Oxygen 4. The fatty acid chain of the lipids is often referred to as a hydrocarbon chain.
Answer:
Explanation:
The following equation relates to Born-Haber cycle

Where
is enthalpy of formation
S is enthalpy of sublimation
B is bond enthalpy
is ionisation enthalpy of metal
is electron affinity of non metal atom
is lattice energy
Substituting the given values we have
-435.7 = 79.2 + 1/2 x 242.8 + 418.7 - 348 +U_L
= - 707 KJ / mol
The moles of oxygen that are produced when 26.5 mol of Al2O3 decomposes is 39.8 mol
<u>calculation</u>
<u> </u> 2Al2O3 + 4Al +3 O2
- use the mole ratio of Al2O3 to O2 to determine the moles of O2.
- that is from the equation above the mole ratio of Al2O3 : O2 is 2:3
- the moles of O2 is therefore=n 26.5 mol x3/2= 39.8 moles