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RN1 e DZV3 C GXGEKOUX6 YS

The document discusses the composition of matter and the kinetic theory of gases, highlighting that all matter consists of molecules that are in constant motion, with their arrangement varying in solids, liquids, and gases. It explains the concepts of intermolecular forces, changes of state, melting points, latent heat, and the effects of pressure on these properties. Additionally, it outlines the law of conservation of mass, stating that mass is neither created nor destroyed in chemical reactions.

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ikrishroy
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11 views3 pages

RN1 e DZV3 C GXGEKOUX6 YS

The document discusses the composition of matter and the kinetic theory of gases, highlighting that all matter consists of molecules that are in constant motion, with their arrangement varying in solids, liquids, and gases. It explains the concepts of intermolecular forces, changes of state, melting points, latent heat, and the effects of pressure on these properties. Additionally, it outlines the law of conservation of mass, stating that mass is neither created nor destroyed in chemical reactions.

Uploaded by

ikrishroy
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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Matter & Its Composition - Law of Conservation of Mass

Kinetic Theory of Gases

1. All matter is made up of molecules.

2. All molecules of a substance are identical.

3. Molecules of different matter differ in composition, shape and size.

4. Molecules are continuously in motion.

5. Intermolecular forces depend on the distance between the molecules and the type
of molecules.

6. Motion of molecules is affected by change in temperature – higher the temperature,


more they move.

Intermolecular Force – The attractive force between the molecules

Arrangement of molecules in Solids

1. Molecules are tightly packed

2. Intermolecular forces are very strong

3. Molecules can only vibrate; no movement is allowed

4. Thus, solids have fixed shape and volume, and cannot be compressed

5. On heating, molecules vibrate more; the distance between the molecules increases
slightly

Arrangement of molecules in Liquids

1. Molecules are slightly further apart than in solids.

2. Intermolecular forces are also less strong.

3. Molecules can move from their positions in liquids.


4. Thus, liquids flow and take the shape of the container.

5. Liquids do not have definite shape, but they do have definite volume.

6. On heating, molecules vibrate and move faster; it only expands slightly

7. Liquids can only be compressed a little.

Arrangement of molecules in Gases

1. Molecules are far apart; hardly any interaction between them

2. Intermolecular forces are negligible.

3. Molecules are free to move around.

4. It has no definite shape or volume.

5. A gas can easily be compressed.

Change of state
A change of state occurs because heat energy breaks the force of attraction
between particles. Kinetic energy of the particle increases.

Melting point
The temperature at which a solid melts into a liquid at normal atmospheric
pressure.
At melting point, the temperature does not change until all solid converts
into liquid.

Latent heat
The heat required to break the force of attraction between the particles at
transition temperature. This heat becomes confined within the material and is
called the latent heat.
Amount of heat required to change 1 kg of material to change its state at
normal atmospheric pressure at transition temperature is called the latent heat
for that transition.

Sublimation
Solid gas [directly]
Example: Ammonium chloride
Effect of change of pressure
If pressure is applied,
Melting point → decreases
Boiling point → increases

Dry Ice – Solid CO2 [directly converts to gas]

Laws of Chemical Combination


Law of conservation of mass
Mass can neither be created nor destroyed in a chemical reaction. It means
that the sum of the masses of the reactants and the products remains the same
during a reaction.

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