UNIT 6: MATTER

UNIT 6: MATTER

INDEX:

1. MATTER

    1.1.-Properties of matter

    1.2.-States of matter

2.- MATTER CHANGES

     2.1.- Physical changes

     2.2.- Chemical changes

3.- PURE AND MIXED SUBSTANCES

     

1.- MATTER ___________________________________________________________________

Ø  Matter is everything that forms the universe and that occupies space.

1.1.- PROPERTIES OF MATTER

Matter has both general and specific properties.

Ø   General properties are common to all types of matter. They are:

·         Mass. It is the amount of matter in an object. Mass is measured in grams or kilograms.

·         Volume. It is the amount  of space an object occupies. Mass is measured in millilitres of litres.

Ø  Specific properties permit us to differenciate between different types of matter. They are:

·         Density. It is the relantioship between an object´s mass and volume.

·         Hardness.

-          Matter is resistant when it is difficult to scratch or cut.

-          Matter is fragile when it is easy to break.

·         Elasticity.

-          Matter is elasctic when it returns to its original shape after stretching or bending it.

·         Water resistant.

-          Matter is waterproof when liquids cannot go throught it.

·         Transparency

-          Matter is transparent when light can pass throught it.

1.2.- STATES OF MATTER.

       Matter exists in three states:

Ø  Solid.

-          It has its own shape.

-          It has the same volume.

Ø  Liquid.

-          It does not have its own shape. It adapts the shape to the container it is in.

-          It always keeps the same volume

Ø  Gas.

-          It does not have its own shape.

-          It does not keep the same volume

ACTIVITIES

1.- Complete the sentences in your notebook

     - The main properties of matter are: __________________ and __________________ .

     - The characteristic properties of matter lets us ____________ them.

     - The states of matter are: ________________ , ________________ and _________________ .

2.- Write the properties to their examples:

      Density ,  Hardness , Elasticity, Transparency and water resistant.

      -  A window lets sunlight in. ___________________ 

     

      -  Bending a rubber toy. _____________________

       - A raincoat protect us from the rain. ___________       

        - Oil floats on water _________________

        - Dropping a glass on the floor. ________________  

     2.-MATTER CHANGES. TYPES OF CHANGE _____________________________________

Ø  Matter changes constantly and does not always stay the same. There are two types of changes: physical and chemical changes.

2.1.- PHYSICAL CHANGES

Ø  The composition of matter does not change, although its appearance, size and temperature are different.

Ø  There are two types of physical changes:

·         Irreversible: the matter cannot go back to its original state.

·         Reversible: The matter can go back to its original state.

Ø  Heat produces other reversible changes in the state:

·         Fusion: A solid becomes a liquid.

·         Evaporation: A liquid becomes a gas.

·         Boiling: An entire liquid reaches a certain temperature and becomes a gas.

·         Condensation: A gas becomes a liquid.

·         Solidification: A liquid becomes a solid

2.2.- CHEMICAL CHANGES

Ø  The composition and properties of matter change during chemical changes, but its mass does not.

For example, the composition and properties of wood change when it burns, but its mass is the same as the sum of the mass of its ashes and smoke.

Ø  There are three types of chemical changes:

·         Oxidation occurs when the oxygen in the air mixes with certain substances. For example, water and oxygen cause oxidation.

·         Combustion occurs when a material mixes with oxygen and it burns. It is a fast oxidation that releases light and heat. Materials like wood, paper or gasoline are combustible because they can burn. For example: Burning a sheet of paper.

·         Fermentation occurs when there is no oxygen and certain living things, like yeasts or some bacteria, help create the chemical change of fermentation. There are two types of fermentation:

-          Natural: when food spoils

-          Artificial: when human makes changes for industrial purposes, like making yoghurt, wine or bread.

3.- PURE AND MIXED SUBSTANCES _____________________________________________

Ø  Pure substances cannot be physically separated into other substances.

Ø  Mixtures are made up of two or more pure substances that can be physically separated. There are two types of mixtures:

·         Heterogeneous

·         Homogeneous

Ø  In  heterogeneous mixtures, we can separate substances in different ways:

·         Filtration: we can separate a solid and a liquid. For example, sand and water.

·         Decantation: We can separate two liquids of different densities. For example, oil and water.

Ø  In homogeneous mixtures, we can separate substances in different ways:

·         Evaporation: we can separate a solid and a liquid. For example, salt and water.

·         Distillation: We use heat to separate different liquids.

ACTIVITIES

1.- Complete the chart.

Separating	Heterogeneous mixtures	Homogeneous mixtures
A solid and a liquid
Two liquids

2.- Correct the sentences.

·         Matter always stay the same.

·         The composition of matter always changes when its appearance changes.

·         A chemical change is when matter changes into something different but doesn´t create a new substance.

·         Physical changes are irreversible when matter can go back to its original state.

·         The changes of state of matter are irreversible.

3.- What´s the difference between pure and mixed substances?

4.- Complete the sentences:

·         In chemical changes, matter can change its ______________ and its ___________, but not its _________ .

·         ____________ , ______________ and ______________are chemical changes.

·         Oxidation occurs when a substance mixes with the oxygen in the _________ and makes a ____________ substance.

·         Combustion is a very _______________ oxidation where a material mixes with oxygen and __________. It releases __________ and __________.