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)

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