Q1:
How much heat, in kilojoules, is released when 0.26 moles of methanol() at are converted to methanol()? Take the of methanol to be kJ/mol. Give your answer to 2 decimal places.
Q2:
Which of the following statements best describes the enthalpy of fusion, ?
- A The change in enthalpy resulting from the combining of two atoms to create a molecule
- B The change in enthalpy resulting from the energy released by a substance when burned in oxygen
- C The change in enthalpy resulting from the release of energy by a substance to change its state from solid to gas at constant pressure
- D The change in enthalpy resulting from the taking in of energy by a substance to change its state from solid to liquid at constant pressure
- E The change in enthalpy resulting from the mixing of two solutions together
Q3:
What is the value of the standard enthalpy of formation of any element in its standard state?
Q4:
The process of dissolution can be considered to involve three steps. Which of the following is not one of these steps?
- A The separation of solvent–solute interactions
- B The separation of solute–solute attractions
- C The formation of solute–solvent interactions
- D The separation of solvent–solvent intermolecular attractions
Q5:
Which of the following has the highest thermal stability?
- A , which has
- B , which has
- C , which has
- D , which has
Q6:
Which of the following statements best defines the standard enthalpy of formation ()?
- A It is the change in enthalpy for the formation of one mole of a compound from its elements, under standard conditions, and with all elements in their standard state.
- B It is the change in enthalpy for the formation of elements from one mole of a compound, under standard conditions, and with all elements in their standard state.
- C It is the change in enthalpy for the decomposition of one mole of a compound to its elements, under standard conditions, and with all elements in their standard state.
- D It is the change in enthalpy for the reaction of one mole of a compound with one mole of another compound to form a mole of products, under standard conditions, and with all elements in their standard state.
- E It is the change in enthalpy for the formation of one mole of crystal from a saturated solution, under standard conditions, and with all elements in their standard state.
Q7:
What standard enthalpy change can be defined as the enthalpy change when one mole of a substance transforms from a liquid state to a solid state under standard conditions?
- A Standard enthalpy of condensation
- B Standard enthalpy of vaporization
- C Standard enthalpy of solidification
- D Standard enthalpy of fusion
- E Standard enthalpy of sublimation
Q8:
Methane reacts with oxygen to produce carbon dioxide and water, according to the following equation.
Using the data in the table provided, what is the standard heat of reaction, ? Give your answer to the nearest whole number.
Q9:
The standard enthalpy change of fusion can be described by this equation:
Using this information, determine the standard enthalpy change for
Q10:
The enthalpy change of solution for with differing amounts of water is shown.
What is the enthalpy change of dilution, ?
Q11:
Give reason: Upon adding a little amount of concentrated sulfuric acid to a beaker containing an amount of water, the temperature of water increases.
- A Because the separation energy of the solute and the solvent is greater than the heat of hydration.
- B Because the separation energy of the solute and the solvent is less than the heat of hydration.
- C Because the separation energy of the solute and the solvent equals the heat of hydration.
- D Because the heat of hydration is higher than the separation energy of the solute but lower than the separation energy of the solvent.
Q12:
Consider the following reaction:
What is the quantity of heat released from the combustion of 32 g of methane? .
- A kJ
- B kJ
- C kJ
- D kJ
Q13:
Why is the standard enthalpy of formation of argon gas equal to zero?
- A Because argon gas has eight electrons in its valence shell
- B Because argon gas is a poor conductor of heat and electricity
-
C
Because argon gas is an
inert gas
- D Because the standard enthalpy of formation of argon gas in its standard state is always zero
Q14:
Calculate, to the nearest whole number, the standard heat of combustion of propane (), its molar mass is 44.1 g/mol, in kilojoules per mole if the change in the heat content of the complete combustion of 10 g of propane is J.
- A kJ/mol
- B kJ/mol
- C kJ/mol
- D kJ/mol
Q15:
Consider the given diagram. If the type of process (exothermic or endothermic) is determined according to the sign of the , which of the following represents the name of the process explained in the diagram and its type?
- A The name of the process is the dehydration process and its type is exothermic (+ve).
- B The name of the process is the dehydration process and its type is endothermic (+ve).
- C The name of the process is the hydration process and its type is endothermic (ve).
- D The name of the process is the hydration process and its type is exothermic (ve).
Q16:
If the separation energy of ammonium nitrate in water is 150 kJ, the hydration energy is 120 kJ, and the separation energy of water is 100 kJ, then this dissolution is .
- A endothermic and the heat of the solution is kJ
- B endothermic and the heat of the solution is kJ
- C exothermic and the heat of the solution is kJ
- D exothermic and the heat of the solution is kJ
Q17:
Arrange the following compounds ascendingly according to their thermal stability.
| The Compound | ||||
|---|---|---|---|---|
- A
- B
- C
- D
Q18:
After studying the given diagram, determine the sign for the value of , , and respectively?
- A Negative, positive, and positive
- B Positive, negative, and positive
- C Positive, positive, and negative
- D Positive, positive, and positive
Q19:
If the dissociation energy of a salt in water is 80 kJ, its heat of solution is kJ, and the separation energy of water is 20 kJ, determine the value of hydration energy and identify whether this is an exothermic or endothermic process.
- A kJ, exothermic process
- B kJ, endothermic process
- C kJ, endothermic process
- D kJ, exothermic process
Q20:
After analyzing the equation below, determine which of the following represents the type of heat change accompanying this process.
- A Standard heat of combustion
- B Standard heat of formation
- C Standard heat of vaporisation
- D Standard heat of solution
Q21:
A compound that has a enthalpy of solution is expected to be in water.
- A highly negative, insoluble
- B highly negative, soluble
- C highly positive, very soluble
- D highly positive, completely soluble
Q22:
The following table shows the standard enthalpies of formation , in kilojoules per mole, of , , and .
| Compound | |||
|---|---|---|---|
| The Standard Enthalpy of Formation |
Which of the following statements is correct?
- A is more thermally stable than .
- B is more thermally stable than .
- C is less thermally stable than .
- D Enthalpy of formation is unrelated to thermal stability.
Q23:
When a student dissolves 1 mol of a certain solute in water, the heat required to separate solvent particles is 40 kJ, the heat required to dissociate the solute particles is 80 kJ, and the hydration energy is 400 kJ. Calculate the heat of the solution and determine whether the process is exothermic or endothermic.
- A kJ, exothermic
- B kJ, endothermic
- C kJ, endothermic
- D kJ, exothermic
Q24:
What kind of heat change is associated with the given process?
- A Heat of combustion
- B Heat of solution
- C Heat of formation
- D Heat of dilution
Q25:
Consider the enthalpies of formation shown in the given table.
| Compound | |||
|---|---|---|---|
| Enthalpies of Formation of the Substances |
Calculate the change in heat content for the reaction
- A kJ/mol
- B kJ/mol
- C kJ/mol
- D kJ/mol
