(a)
Write the balanced half-reactions for the overall process:
Oxidation: Se^2- (aq) → Se
(s) + 2e-
Reduction: 2So3^2- (aq) + 3H2O (l) + 4e- →
S2O3^2- + 6OH- (aq)
(b)
Assuming E sulfite is 0.57 V, compute E selenium:
E anode = E cathode – E cell
= -0.57 – 0.35
=
-.092
Answer:
The enthalpy of the second intermediate equation is altered by halving its value and changing the sign.
Explanation:
Let's examine both the first and second intermediate reactions alongside the overall equation concerning the examined process;
First reaction;
Ca (s) + CO₂ (g) + ½O₂ (g) → CaCO₃ (s) ΔH₁ = -812.8 kJ
Second reaction;
2Ca (s) + O₂ (g) → 2CaO (s) ΔH₂ = -1269 kJ
Thus, the overall reaction becomes;
CaO (s) + CO₂ (g) → CaCO₃ (s) ΔH =?
According to Hess's law, which states that the total heat change in a reaction is equal to the sum of the heat changes for each step, we cannot simply sum the enthalpies for this overall reaction. Instead, we obtain the overall enthalpy by halving the second intermediate reaction's enthalpy and changing its sign before adding, as illustrated below;
Enthalpy of Intermediate reaction 1 + ½(-Enthalpy of Intermediate reaction 2) = Enthalpy of Overall reaction
The change in temperature can be expressed as:
By substituting in the known values, we arrive at:
Thus, we obtain the required answer.
To solve for density, you can use the formula--> Density= PM/ RT, where P stands for pressure, M for molar mass, R represents the gas constant, and T is temperature.
P= 1.75 atm
M= 16.01 g/ mol
R= 0.0821 atm·L/ mol·K
T=337 k
Thus, the density calculation becomes: density= (1.75 x 16.01)/ (0.0821 x 337)= 1.01 g/L
The equation representing the reaction between sodium bicarbonate and hydrochloric acid is as follows:
The substances 
and 
combine in a 1:1 ratio. Therefore, we calculate the quantity of sodium bicarbonate and its molar mass to determine the moles formed.
.
.
We also recognize that the stoichiometric proportions are 1:1:1:1:1, which leads to the conclusion that the moles of 
equal 24.977 moles.
Next, we apply the ideal gas equation 
, where P denotes pressure, V refers to volume, R is the gas constant, and T represents the temperature in kelvins. We rearrange to solve for V
The final answer should be expressed in liters, 
, hence
