So technicaly the answer is D
Answer:
Option c → Tert-butanol
Explanation:
To solve this, you have to apply the concept of colligative property. In this case, freezing point depression.
The formula is:
ΔT = Kf . m . i
When we add particles of a certain solute, temperature of freezing of a solution will be lower thant the pure solvent.
i = Van't Hoff factor (ions particles that are dissolved in the solution)
At this case, the solute is nonvolatile, so i values 1.
ΔT = Difference between fussion T° of pure solvent - fussion T° of solution.
T° fussion paradichlorobenzene = 56 °C
T° fussion water = 0°
T° fussion tert-butanol = 25°
Water has the lowest fussion temperature and the paradichlorobenzene has the highest Kf. But the the terbutanol, has the highest Kf so this solvent will have the largest change in freezing point, when all the molalities are the same.
Answer:
253.02 kJ.
Explanation:
The balanced reaction for the decomposition of baking soda is
2 NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g)
We can find the heat of reaction by using the Hess' Law. This is done by using this formula:
∑(Hf,products) -∑(Hf,reactants) = Heat of reaction
where Hf is the heat of formation. According to literature, these are the heats of formation for each of the compounds in the reaction:
NaHCO3: -947.68 kJ/mol
Na2CO3: -1130.94 kJ/mol
CO2: -393.51 kJ/mol
H2O: -241.8 kJ/mol
Applying Hess' Law:
[1(-1130.94) + 1(-241.82)] + 1(-393.51)] - [2(-947.68)] = 129.09 kJ
Thus, the heat of reaction is 129.09 kJ/mol NaHCO3. Since there is 1.96 mol of NaHCO3, the total heat of reaction is 253.02 kJ.
Divide by 1000
145÷1000=0.145
Hope this will be helpful.