Calculate the amount of heat (in kJ) released when converting 150.2 g of water to ice at -23 degrees Celsius. 2. A closed vessel of volume 10.0 L initially contains 1.303 g of water and no water vapor. Please calculate the mass of liquid water remaining once the system reaches equilibrium at 30 degrees Celsius. The vapor pressure of water at that temperature is equal to 0.0418 atm. 3. A person drinks four glasses of cold water (5 degrees C) every day. The volume of each glass is 195. mL. How much heat (in kJ) does the body have to supply to raise the temperature of the water to 37 degrees C (body temperature)? 4.From these data: N2H4(l) + O2(g) à 2N2(g) + 2H2O(l) H= -622.2 kJ/mol H2(g) + ½O2 à H2O(l) H= -285.8 kJ/mol H2(g) + O2(g) à H2O2(l) H= -115 kJ/mol Find H for the reaction: N2H4(l) + 2H2O2(l) à 2N2(g) + 4H2O(l) 5. Consider the following chemical equation. CH4(g) + 2O2(g) à CO2(g) + 2H2O(l) Using the values in the table, calculate the standard enthalpy change. CO2(g) = -393.5 kJ/mol O2(g) = 0 kJ/mol H2O(g) = -241.8 kJ/mol H2O(l) = -285.8 kJ/mol CH4(g) = -74.85 kJ/mol SO2(g) = -296.4 kJ/mol SO3(g) = -395.2 kJ/mol 6. A solution is prepared by dissolving 396g of sucrose (C12H22O11) in 624 g of water. What is the vapor pressure of this solution at 30 degrees Celsius? (The vapor pressure of water is 31.8 mmHg at 30 degrees Celsius). 7. Suppose that you make a solution by dissolving 325 g of glucose C6H12O6 in 525 g of water. Please predict the vapor pressure of this solution at 30.0 degrees Celsius if the normal vapor pressure of water at that temperature is 0.0418 atm.
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
1. Calculate the amount of heat (in kJ) released when converting 150.2 g of water to ice at -23 degrees Celsius.
2. A closed vessel of volume 10.0 L initially contains 1.303 g of water and no water vapor. Please calculate the mass of liquid water remaining once the system reaches equilibrium at 30 degrees Celsius. The vapor pressure of water at that temperature is equal to 0.0418 atm.
3. A person drinks four glasses of cold water (5 degrees C) every day. The volume of each glass is 195. mL. How much heat (in kJ) does the body have to supply to raise the temperature of the water to 37 degrees C (body temperature)?
4.From these data:
-
- N2H4(l) + O2(g) à 2N2(g) + 2H2O(l) H= -622.2 kJ/mol
- H2(g) + ½O2 à H2O(l) H= -285.8 kJ/mol
- H2(g) + O2(g) à H2O2(l) H= -115 kJ/mol
Find H for the reaction:
N2H4(l) + 2H2O2(l) à 2N2(g) + 4H2O(l)
5. Consider the following chemical equation.
CH4(g) + 2O2(g) à CO2(g) + 2H2O(l)
Using the values in the table, calculate the standard enthalpy change.
CO2(g) = -393.5 kJ/mol
O2(g) = 0 kJ/mol
H2O(g) = -241.8 kJ/mol
H2O(l) = -285.8 kJ/mol
CH4(g) = -74.85 kJ/mol
SO2(g) = -296.4 kJ/mol
SO3(g) = -395.2 kJ/mol
6. A solution is prepared by dissolving 396g of sucrose (C12H22O11) in 624 g of water. What is the vapor pressure of this solution at 30 degrees Celsius? (The vapor pressure of water is 31.8 mmHg at 30 degrees Celsius).
7. Suppose that you make a solution by dissolving 325 g of glucose C6H12O6 in 525 g of water. Please predict the vapor pressure of this solution at 30.0 degrees Celsius if the normal vapor pressure of water at that temperature is 0.0418 atm.
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