CHAPTER 1: REACTION KINETIC (PART 3)

 1.3: Factors Affecting Reaction Rate

The sentences with red color are the main point in explaining factors of concentration, pressure, particle size & temperature affecting reaction rate.

***For temperature & catalyst, they are related with the activation energy

FACTOR - Temperature

If the explanation about general effect of Temperature to the rate of reaction, we use the explanation given above.

If specifically explanation about effect of 2 different Temperature to the rate of reaction, we must refer to MAXWELL - BOLTZMANN DISTRIBUTION CURVE

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Diagram 1: Energy profile of exothermic & endothermic (with & without catalyst)

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CALCULATION USING ARRHENIUS EQUATION

Temperature & Activation energy with presence of catalyst are involved in Arrhenius equation. Thus, we must know the effect when change on Temperature & Activation Energy occur.  

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***R = gas constant (8.314 J/mol K)

Arrhenius equation also can be used as graphical method like integrated rate law in Chapter 1.1: Reaction Rate.

But we use the Arrhenius equation for graphical method using

 ln k = -Ea/R (1/T) + ln A

*** it must obey y = mx + c method in plotting the graph

Therefore, Graph ln k against 1/T will be plotted

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Arrhenius Equation using for calculation

Normally, this equation is used when we have 2 different temperature with different rate constant, k.

SEM 2 REACTION KINETIC (PART 2)

 1.2: COLLISION THEORY

COLLLISION THEORY ONLY OCCUR WHEN:- 

Chart 1: Criteria of Collision Theory

Diagram 1: Type of Collision

In CHEMISTRY, focus on EFFECTIVE COLLISION. 

Chemical reaction that produce PRODUCT very important & occur because of EFFECTIVE COLLISION

Chart 2: Criteria of Effective Collision

One of the criteria to form EFFECTIVE COLLISION is colliding molecules possess a minimum energy (ACTIVATION ENERGY)

WHAT IS ACTIVATION ENERGY?

Ø Activation energy (E_a), is the minimum energy required for effective collisions in order to initiate a chemical reaction

Diagram 2: Analogy of Activation energy

Normally, chemical reaction without catalyst has higher peak for activation energy. Thus, the rate of reaction become very slow.

Chemical reaction with catalyst has lower peak for the activation energy. Thus, the rate of reaction become very fast.

The peak of activation energy can be seen in the ENERGY PROFILE DIAGRAM. There are 2 type of chemical reactions (EXOTHERMIC & ENDOTHERMIC) that can represent by energy profile diagram. 

Table 1: Comparison of Energy Profile for Exothermic & Endothermic Reaction

TRANSITION STATE is occurred  in the area of ACTIVATION ENERGY with MAXIMUM POTENTIAL ENERGY.

During the chemical reaction, the collision is happened & if the effective collision form, ACTIVATED COMPLEX (TEMPORARY SPECIES) will produce at the stage we called TRANSITION STATE

This diagram to show where the ACTIVATED COMPLEX is temporarily produced.

SEM 2: CHAPTER 1: REACTION KINETIC (PART 1)

 1.1 : REACTION RATE

TABLE 1: SUMMARY OF REACTION RATE OF ZERO, FIRST & SECOND ORDER

There are 4 ways to determine order of reaction:

1. Refer to the unit of RATE CONSTANT, k

- each order has different unit of k.

- For example: 

   👉 ZERO ORDER - k = M/time or mol/L time or mol/dm3 time

   👉 FIRST ORDER - k = time-1 

   👉 SECOND ORDER - k = M-1 time-1 or L mol-1 time-1  or  dm3 mol-1 time-1

2. Initial Rate Method 

- comparing data based on given table of concentration with initial rate

3. Half life Method

TABLE 2: Comparing Half life method to determine Zero, First & Second Order

4. Linear Graph Method

- To plot Linear graph, we refer to integrated rate law 

CHAPTER 5.1: GAS

  CHAPTER 5: STATE OF MATTER

CHAPTER 5.1 : GAS

Chart 1: Behaviour of Ideal Gas based on Kinetic Molecular Theory Of Gas

Diagram 1: Summary of Gases Laws

* Ideal gas always obey all the gases law

*TIPS:

  Students can only remember ideal gas equation, PV = nRT that actually          represent the ABC LAW

    A ⇒ AVOGADRO'S LAW

    B ⇒ BOYLE'S LAW

    C ⇒ CHARLES'S LAW

    Let see how does it work

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  DALTON'S LAW  ⇛ PT = PA + PB + PC + ......

   DEFINITION:

The total pressure of a mixture of non-reacting gases in a system is the sum of their partial pressures exerted by each of the gas in the mixture.

    Mixture of non-reacting gases in a system

      👉 EACH OF THE GAS in the container do not react with one another                to produce another gas.

    Sum of their partial pressures 

      👉 TOTAL PRESSURE in the container based on pressure represent                 for each gas when they are mixed together.     

***TIP

    - DALTON'S LAW ONLY APPLY WHEN IT IS INVOLVED OF A SYSTEM                                 (CONTAINER/VESSEL) WITH NON-REACTING GASES MIXTURE

CALCULATION OF DALTON'S LAW 

In 

1. normal closed vessel/container

2. water displacement method

NORMAL CLOSED VESSEL/CONTAINER

To calculate the pressure of each gas, students can use either 

1. PV = nRT (IDEAL GAS EQUATION) or 

2. P1V1 = P2V2 (BOYLE'S LAW) or

3. P1V1 = P2V2     (COMBINE LAW) or 

       T1         T2

4. PA = PTXA

         

WATER DISPLACEMENT METHOD

To calculate the pressure of gas collected over water, normally the pressure in unit mmHg & formula used is PT = Pgas + Pwater vapour .

Diagram 2: Simple explanation on Collecting Gas over Water using Water Displacement Method

IDEAL GAS & REAL GAS

* Main idea to explain the different between ideal gas & real gas is using 3rd & 4th assumption from KINETIC MOLECULAR THEORY OF GAS which are

💟Volume of gas molecules are negligible compare to volume of the container
💟Intermolecular forces ( or attractive and repulsive force) between gas molecules is negligible.

                            TABLE 1: Comparison between Ideal Gas & Real Gas

In discussing about IDEAL & REAL GAS, 2 factors that affect the behaviour of the gas:

1. TEMPERATURE

2. PRESSURE

To explain the BEHAVIOUR OF GAS, there 2 CONDITIONS:

1. REAL GAS APPROACHES IDEAL GAS

* KEYPOINT : T↑ , Kinetic Energy ↑, Gas behave ideally

                        P↓ , Vcontainer ↑, IMF negligible , Gas behave ideally

                TABLE 2: EXPLANATION ON REAL GAS APPROACHES IDEAL GAS

2. REAL GAS DEVIATE FORM IDEAL GAS

* KEYPOINT : T↓ , Kinetic Energy ↓, Gas behave ideally

                        P↑ , Vcontainer ↓ , IMF significant, Gas behave ideally

                TABLE 3: EXPLANATION ON REAL GAS DEVIATES IDEAL GAS

***PLEASE DO EXERCISES PAGE 18 & 23 after you have finished your reading on this blog.

***FILL IN THIS FORM BEFORE 10.15 am (Monday, 09/11/2020)

    EXIT TICKET

DISCUSSION ON INTERMOLECULAR FORCES & METALLIC BOND

 INTERMOLECULAR FORCES

In answering question of IMF, make sure understand about POLARITY OF THE MOLECULES

- if the molecules is 

a) NON POLAR , thus its IMF is LONDON DISPERSION FORCES

b) POLAR , thus its IMF is DIPOLE-DIPOLE FORCES or HYDROGEN BOND

1. What type of intermolecular forces are due to the attraction between temporary dipoles and their induced temporary dipoles?

* If this kind of question, please understand the definition of each type of INTERMOLECULAR FORCES. 

Keypoints: attraction between temporary dipoles and their induced temporary dipoles

ANSWER:

LONDON DISPERSION FORCES 

⇰because LONDON DISPERSION FORCES is a force of attraction between *instantaneous(temporary) dipole* that arise from a short time scale fluctuation in the electronic structure of species when they become very close to one another (induced temporary dipoles).

2. What type of interparticle forces holds liquid N₂ together?

* INTERPARTICLE = INTERMOLECULAR 

BUT Interparticle always used when involves simple molecules

Liquid N_{2   is NONPOLAR}

ANSWER: 

N_{2 has LONDON DISPERSION FORCES}

_3. Which   of   the   following   will   have   hydrogen   bonding? 

    H3CCH2CH2OH     CH3CH2OCH3        CH3CH2NH2           CH3CH2SH  

    

                            STRUCTURE 1 : Molecules have Hydrogen bond between its                                                                         molecules

                            STRUCTURE 2 : Molecules have Hydrogen bond between its                                                                         molecules

                            STRUCTURE 3 : Molecules do not have Hydrogen bond between its                                                             molecules 

                            STRUCTURE 4 : Molecules do not have Hydrogen bond between its                                                             molecules 

ANSWER: H3CCH2CH2OH and CH3CH2NH2  

4. Which of the molecules has higher boiling point, CH3CH2OH or CH3OCH3 ?

Both molecules have molecular weight = 46g/mol

But they have difference intermolecular forces among its own molecules.

CH3CH2OH  has hydrogen bond between its molecules but CH3OCH3 has dipole-dipole forces between its molecules

Thus, CH3CH2OH has higher boiling point than CH3OCH3     

ANSWER: CH3CH2OH

METALLIC BOND

1.  Describe   the   structure   of   a   metal. 

Explanation on the structure in ELECTRON SEA MODEL

ANSWER: 

Giant   structure   of   atoms  arranged   in   an array pattern

2.  Describe   the   position   of   electrons  in   a   metal. 

Explanation must highlight on the DELOCALIZED OF ELECTRONS

ANSWER:

The electron delocalized around the metal ion

3. Draw   a   diagram   to   represent   a   metal,  representing   the   electrons   and   the   respective   charges.  

Explanation based on the structure in ELECTRON SEA MODEL. Give any example of metal element

ANSWER:

4. What   are   the   structural   differences   between   a   pure   metal   and   an   alloy? 

ANSWER:  

 A   pure   metal   contains   atoms   of  the   same   metal   whereas   an   alloy   is   compiled   of   different   metal  atoms.

 In   pure   metals,  the   atoms   are   arranged   in   layers   /  alloys   have   distorted   layers.  

5. Fill in the box with correct answer

ANSWER:

*This post just to share the idea on variety of questions in the IMF & Metallic bond.

Please give some comment on roughly idea of IMF & Metallic Bond in the COMMENT POST as I can know your presence in reading this post. TQ.

4.5: METALLIC BOND

Metallic Bonding

DEFINITION: The electrostatic force between the positively charged metal ions and the ‘sea’ of delocalized valence electrons.

HOW DOES IT WORK?                                                                                                     

Diagram 1: Formation of Metallic Bond

               Diagram 2: Example of metallic bond (Na) in 'Electrons Sea Model'

             Diagram 3: Example of metallic bond (Mg) in 'Electrons Sea Model'

When the number of valence electrons increases in a metal, the strength of metallic bonding increases.

Requirement to draw ELECTRON SEA MODEL in order to show METALLIC BOND: -

1) Number of atom in each a row is at least 2 atoms.

    - they must be in straight line

2)The number of valence electrons & number of metal atoms must be accurately shown in the 'Electrons Sea Model'.

- Example: if in the model you want to show 4 atoms of Na, and each Na has                    1 valence electrons. Thus it must have 4 valence electrons                                shown. 

*** To explain formation of Metallic bond, refer to DIAGRAM 1 & draw 'Electrons Sea Model' .                   

***MELTING & BOILING POINT IN PERIOD 3 

    Please read this part in the lecture notes

GOOGLE FORM CHAPTER 4.5

*** all of my students need to fill in this form before MONDAY (2/11/2020, 5PM). Your response is taken as attendance of  tutorial.TQ. 

4.4: INTERMOLECULAR FORCES

INTERMOLECULAR FORCES (IMF)

Intermolecular forces is one of the way for the molecules to communicate with its own molecules or with the other molecules. The interaction among the molecules will form either, Dipole - Dipole forces, Hydrogen Bond or Ionic Bond. 

OVERALL OF INTERMOLECULAR FORCES

In Chapter 4.2( Molecular Geometry & its polarity of the molecules), you have learned about determining the polarity of the molecules. Moreover, the polarity of the molecules will indicate the type of intermolecular forces of its molecules.

As the beginning of the topic INTERMOLECULAR FORCES, firstly, lets learn about VAN DER WAALS FORCES. 

There are 2 type of Van Der Waals Forces which are:-

1. London Dispersion Forces Or London Forces

2. Dipole - dipole Forces

LONDON DISPERSION FORCES

DEFINITION:

Force of attraction between instantaneous dipole that arise from a short time scale fluctuation in the electronic structure of species when they become very close to one another.

HOW DOES IT FORMS?

Diagram 1: Explanation for the Formation of London Dispersion Forces

All molecules whether it is polar or nonpolar or ions, they have London Dispersion forces when they interacts with their molecules or other molecules.

 ⇒⇒ Examples: H2 (molecules), ICl2 + (ion), CH3Cl (molecule) 

DIPOLE - DIPOLE FORCES (DD)

DEFINITION: Force of attraction between negative end of permanent dipole of one molecule and the positive end of permanent dipole of another molecule.

HOW DOES IT FORMS?

Diagram 2: Explanation for the Formation of Dipole-dipole Forces

     

Diagram 3: Example of molecules of greater polarity of molecules with greater dipole-dipole forces

*** KEYPOINTS: Type of IMF for

1) Polar molecules - London dispersion forces & Dipole - dipole Forces

2) Nonpolar molecules - London dispersion forces  

 FACTORS THAT AFFECTING THE STRENGTH OF VAN DER WAALS FORCES

Chart 1: Summary of Factors Affecting The Strength of VDW Forces

This is just brief explanation of the factors Affecting The Strength of VDW Forces. Refer to the lecture notes on this part for some example & explanation of the topic.

HYDROGEN BOND (HB)

DEFINITION: Attractive forces between the positively charged H atom of a polar molecule and the negatively charged electronegative atom (F, O, N) of another molecule

*The interaction is between H from one polar molecules (H is must directly bonded to F or O or N in its molecules) with F,O,N from the other polar molecules

EXAMPLES:

Diagram 4: Interaction between 2 molecules in order to form Hydrogen Bond

*** Hydrogen Bond is weaker IMF than Ionic Bond 

*** But, Hydrogen Bond is stronger IMF than London dispersion forces & Dipole - dipole forces

Effect of Hydrogen bonding on physical properties

Chart 2: Summary about the effect of Hydrogen Bond in the molecules

Diagram 5: Differences between structure in ICE (SOLID) & WATER (LIQUID)

EXAMPLE OF IMF AMONG MOLECULES

1. HF molecules

    - is POLAR MOLECULES

    - contains of Hydrogen bond, Dipole - dipole forces & London dispersion forces              between its molecules

    - the MOST DOMINANT IMF in HF molecules is HYDROGEN BOND

2. HBr molecules

    - is POLAR MOLECULES

    - contains of Dipole - dipole forces & London dispersion forces between its                      molecules

    - the MOST DOMINANT IMF in HBr molecules is DIPOLE - DIPOLE FORCES

3. CH4 molecules

    - is NONPOLAR MOLECULES

    - contains of London dispersion forces between its molecules

    - the MOST DOMINANT IMF in CH4 molecules is LONDON DISPERSION FORCES

4. SF6 molecules

    - is NONPOLAR MOLECULES

    - contains of London dispersion forces between its molecules

    - the MOST DOMINANT IMF in SF6 molecules is LONDON DISPERSION FORCES

5. Interaction between H2O with CH4

    - H2O is POLAR MOLECULES 

    - contains of Hydrogen bond, Dipole - dipole forces & London dispersion forces between its molecules   

     

    - CH4 is NONPOLAR MOLECULES

    - contains of London dispersion forces between its molecules

  

    -Thus, the interaction between both molecules is LONDON DISPERSION FORCES

* Do exercises on IMF (LECTURE NOTES). 

* Please write some comment on this post as I know you have read my blog on this topic. TQ😍

GOOGLE FORM 4.4

All of my students must answer this form before SUNDAY (1/11/2020, 6PM). Upon your response is taken has attendance of tutorial. tq