We are asked to find the value of ΔG°rxn from the equilibrium concentrations of the reactants and products. We can use the following formula:
ΔG°rxn = -RTlnK
The value of R = 8.314 J/Kmol, T = 298.15 K and we are given the equilibrium constant Keq = 2.82.
The question provides equilibrium concentrations and then asks to find ΔG°rxn when more of a product is added to the reaction mixture. However, you are asked to find ΔG after the reaction has settled down and reached equilibrium once more. Therefore, we can simply use Keq = 2.82 still and solve for ΔG.
ΔG°rxn = -(8.314 J/Kmol)(298.15 K)(ln(2.82))
ΔG°rxn = -2570 J/mol
ΔG°rxn = -2.57 kJ/mol
Under equilibrium conditions at standard temperature and pressures, the value of ΔG°rxn = -2.57 kJ/mol.
For this question, you must know that there are 6.022e23 atoms/molecules per mole of any substance (this is Avogadro's number). Therefore, your answer is 6.022e23 * 1.60 = 9.64e23 molecules of sulfur dioxide. (the "e" represents "times ten to the power of ___ ")
When water at 50 C is added to ice at -12 C, heat is transferred from hot water to ice.
- Heat given out by water = Heat absorbed by ice
Calculating the heat released by hot water:
ΔT
Calculating heat absorbed by 16 g of ice: Ice at 
is converted to ice at 
and then ice at 
to water at 
ΔT + 
+ 
q = 405.12 J +5336.8 J =5741.92 J
- Heat given out by water = Heat absorbed by ice
-(
m = 27.4 g
Therefore, 27.4 g water at 
must be added to 16 g of ice at 
to convert to liquid water at
