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1. Describe how chemical energy related to the heat lost or gained in chemical reactions (Exothermic and Endothermic reactions)

Energy is the ability to do work or produce heat.
Energy exists in two basic forms: potential energy and kinetic energy.
The potential energy of a substance depends on its composition: the type of atoms, the number and type of chemical bonds, and how the atoms are arranged
The law of conservation of energy states that in any chemical reaction or physical process, energy is neither created nor destroyed.

This is also known as the first law of thermodynamics.

Chemical potential energy is energy stored in a substance because of its composition

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Endothermic

Exothermic

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Q2. Perform interconversion between units of heat [ page 7 example 1 ]

Option 1

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2. Perform interconversion between units of heat [ page 7]

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Q3. Solve problems involving changes in temperature and state using the equations ( Q=mcΔT) [ page 10 example 2 ]

A 4.50 g of pure gold absorbed 276 J of heat. The initial temperature was 25.0 degree Celsius. What is the final temperature ?
ANALYZE THE PROBLEM [ underline or highlight what’s given]
A 4.50 g of pure gold absorbed 276 J of heat. The initial temperature was 25.0 degree Celsius. What is the final temperature ?

q = c × m × ΔT

ΔT = q/ m x c

T2 – 25 = 276 / 4.50 X 0.129

T2- 25 = 475.45

T2 = 475.45 + 25

= 500.45

3 s.f.

Ans = 500 degree Celsius .

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3. Solve problems involving changes in temperature and state using the equations (e.g. Q=mcΔT) [ page 10]

problems involving changes in temperature and s
When a sample of water absorbs 5650 J of heat its temperature increases from 20.0℃ to 46.6℃. Calculate the mass of sample of water (Specific heat capacity of water is 4.184 J/g.℃).

m = Q /c × ΔT
=5650/ 4.184 × (46.6 − 20.0)
m = 50.8 g 10

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Q4. Describe the two types of calorimeter (Bomb calorimeter & Foam-cup calorimeter)

Which of the following statements does not apply to calorimeter?

A) measures the amount of heat produced or absorbed.
B) determines the specific heat of an unknown substance
C) change in the temperature of the amount of water represents the data collected from the calorimeter.
D) engine generation of friction leads to an accuracy in measuring the temperature.

Option D

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Describe the two types of calorimeter (Bomb calorimeter & Foam-cup calorimeter)

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Q5. Predict the type of chemical reaction (exothermic, endothermic) page 14 �Marks per Main Question�يتنبأ بنوع التفاعل الكيميائي مثل تفاعل طارد للحرارة وتفاعل ماص للحرارة�الدرجات لكل

Option D

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6. Compare and contrast potential energy diagrams of exothermic and endothermic reactions in terms of general shape, enthalpy of reactants and products, and enthalpy change of reaction and its sign (page 17 )

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7. Write thermochemical equation for the changes of state (vaporization, fusion, condensation and solidification) [ Page 20]

What does a positive value for delta H mean in this case ?

Liquid to gas is called vaporization and solid to liquid is called fusion.

The above two reactions are endothermic in nature which means reactants absorb energy to form products and therefore products have greater energy than reactants. Hp > Hr [ endo]

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Changes of State

Upward arrows show: energy of the system increases.

Downward arrows show: energy of the system decreases.

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8. Perform calculations using enthalpy of combustion [ page 22 ]

How much heat is evolved when 54.0 g glucose (C₆H₁₂O₆) is burned according to this equation?

C₆H₁₂O₆(s) + 6O₂(g)→ 6CO₂(g) + 6H₂O(l) ΔH_comb = -2808 kJ

Grams

Divide by molar mass

Moles

Multiply by enthalpy of 1 mole

Enthalpy

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Perform calculations using enthalpy of combustion

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9. Solve the problems related to the energy changes in the chemical reaction using Hess's Law [ Page 24-26]

Option d

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10. Define standard enthalpy of formation of a compound, determining on what basis it is defined [ Page 27 , 28, 29, 30 ]

Equation [ page 30]

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11. Identify the standard enthalpy (heat) of formation of a free element in its standard state [ Page 28]

Elements in their standard state have been given value 0 for standard enthalpy of formation
Standard states do not have zero energy but to give standard value its taken as zero.

Option A

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12. Illustrate the relation between enthalpy change (ΔH) and the tendency of a reaction to occur

Only with delta H value we cannot conclude whether a reaction is spontaneous or not.
Some exothermic reactions are spontaneous e.g. rusting
But even ice melting is spontaneous which is endothermic.

Hence , we define another term entropy and free energy to determine reaction spontaneity.

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13. Explain the relationship among the signs of ΔG, ΔH, ΔS that lead to spontaneous or non-spontaneous reaction taking into consideration temperature conditions . [ page 33, 34,35,36]

Reaction Spontaneity ΔG_system = ΔH_system – TΔS_system
ΔH_system	ΔS_system	ΔG_system	Reaction Spontaneity
negative	positive	always negative	always spontaneous
negative	negative	negative or positive	spontaneous at lower temperatures
positive	positive	negative or positive	spontaneous at higher temperatures
positive	negative	always positive	never spontaneous

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13.

Convert unit of entropy to kJ/K

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14. Calculate the free energy value )ΔG( and use it to determine the tendency of a reaction to occur

For a process, ΔH_system = 145 kJ and ΔS_system = 322 J/K. Is the process spontaneous at 382 K?

The reaction is non-spontaneous as free energy is positive .

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15. Describe chemical equilibrium using reactant and product concentration-time graph

The law of chemical equilibrium states that at a given temperature, a chemical system might reach a state in which a particular ratio of reactant and product concentrations has a constant value.

Page 81 and 82

Figure 2 and 3

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16. Relate the value of an equilibrium constant to the relative quantities of reactants and products at equilibrium while identifying the information provided by the value of K for a given equilibrium system at a specified temperature

K_eq> 1: Products are favored at equilibrium.

K_eq< 1: Reactants are favored at equilibrium

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Relate the value of an equilibrium constant to the relative quantities of reactants and products at equilibrium while identifying the information provided by the value of K for a given equilibrium system at a specified temperature

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17. Explain the effect of changing the concentration (Adding reactants or removing products or adding products) on an equilibrium system

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17. Explain the effect of changing the concentration (Adding reactants or removing products or adding products) [ Page 95 ]

Option c

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18. Explain the effect of changing the volume and pressure on an equilibrium system� [ page 96 ]