Answer:
0.758 V.
Explanation:
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In this case, case when we include the effect of concentration on an electrochemical cell, we need to consider the Nerst equation at 25 °C:
Whereas n stands for the number of moles of transferred electrons and Q the reaction quotient relating the concentration of the oxidized species over the concentration of the reduced species. In such a way, we can write the undergoing half-reactions in the cell, considering the iron's one is reversed because it has the most positive standard potential so it tends to reduction:
It means that the concentration of the oxidized species is 0.002 M (that of nickel), that of the reduced species is 0.40 M and there are two moles of transferred electrons; therefore, the generated potential turns out:
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A teaspoon of caffeine is <em>NOT</em> deadly as teaspoon of ricin
The independent variable is a variable that is being manipulated or controlled. This is to see how it affects, changes and yields the outcome of the particular stimuli.
The dry ice experiment has an IV of temperature and a DV of melting time.
DE = dH - PdV
<span>2 H2O(g) → 2 H2(g) + O2(g) </span>
<span>You can see that there are 2 moles of gas in the reactants and 3 moles of gas in the products. </span>
<span>1 moles of ideal gas occupies the same volume as 1 mole of any other ideal gas under the same conditions of temp and pressure. </span>
<span>Since it is done under constant temp and pressure that means the volume change will be equal to the volume of 1 mole of gas </span>
<span>2 moles reacts to form 3 moles </span>
<span>The gas equation is </span>
<span>PV = nRT </span>
<span>P = pressure </span>
<span>V = volume (unknown) </span>
<span>n = moles (1) </span>
<span>R = gas constant = 8.314 J K^-1 mol^-1 </span>
<span>- the gas constant is different for different units of temp and pressure (see wikki link) in this case temp and pressure are constant, and we want to put the result in an equation that has Joules in it, so we select 8.314 JK^-1mol^-1) </span>
<span>T = temp in Kelvin (kelvin = deg C + 273.15 </span>
<span>So T = 403.15 K </span>
<span>Now, you can see that PV is on one side of the equation, and we are looking to put PdV in our dE equation. So we can say </span>
<span>dE = dH -dnRT (because PV = nRT) </span>
<span>Also, since the gas constant is in the unit of Joules, we need to convert dH to Joules </span>
<span>dH = 483.6 kJ/mol = 483600 Joules/mol </span>
<span>dE = 483600 J/mol - (1.0 mol x 8.314 J mol^-1K-1 x 403.15 K) </span>
<span>dE = 483600 J/mol - 3351.77 J </span>
<span>dE = 480248.23 J/mol </span>
<span>dE = 480.2 kJ/mol </span>
Explanation:
Moles of N2 = 35.0g / (28g/mol) = 1.25mol
Moles of H2 = 60.0g / (2g/mol) = 30.0mol
Since 1.25mol * 3 < 30.0mol, nitrogen is limiting.
Moles of NH3 = 1.25mol * 2 = 2.50mol.
Mass of NH3 = 2.50mol * (17g/mol) = 42.5g.
30.0mol - 1.25mol * 3 = 26.25mol.
Excess mass of H2
= 26.25mol * (2g/mol) = 52.5g.
