MATTER

1.- Introduction.

Matter is all what we see, smell or touch. It can be hard as iron, fragile as glass, viscous as oil...

In this unit we will study matter, some of its properties and changes the heat produces in its state, and even on its composition. Also we learn about the difference between physical changes and chemical changes of matter and some chemical changes that happen in living organisms.

2.- Matter.

The universe is composed of matter: stars, planets, mountains, rocks, sand, clouds, etc. But, in the universe, there are things that they are not matter: the light, sound, heat, electricity...

What are the differences between the previous substances ? First we must to define what is matter:

3.- General and specific properties.

Matter has many properties: strength, temperature, flexibility, brightness, mass, volume, transparency, solubility, etc. However, not all them we will serve to differentiate between some bodies.

The properties of matter can be classified in:

I. General properties. Those are not used to distinguish what type of substance it is. They are mass, volume and temperature.

II. Specific properties . They are depend on the kind of substance that is made. Serves to differentiate a substance of another. They are odor, solubility, density.

4.- The states of matter.

The main states of matter are solid, liquid and gas. The state in which we find matter depends on the temperatura and pressure. A piece of iron or a stone are matter in solid state. Water and oil are

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Matter is everything that has mass and that occupies a space.

Two different material systems cannot have the same specific properties.

matter in liquid state. Nitrogen and oxygen are matter in gaseous state. In each state, matter has different properties.

Solids have constant volume and shape. Their shape and volume don´t change when we put them in a different container. Their particles are not compressed because they are together and strongly united. The particles only present vibration movement

Liquids have a constant volume but not shape of their own. If we pass a litre of water from a bottle to a pitcher, the water takes the form of the pitcher but its volume doesn´t change. Their particles almost are not compressed and they are at a fixed distance and movement. The particles can slip some over others.

Gases change volume and shape. Gases compress easily because their particles are widely separated and move freely. When you click a balloon, air escapes and extends across the room. It passed to the form and the volume of the room.

Solid Liquid Gas

Both liquids and gases are fluid. They can pass through a hole in a solid and can be driven tubes.

We can summarize the matter states and its properties in the following table:

SOLIDS LIQUIDS GASESHave their own form. Don´t have their own form. Don´t have their own form.Have constant volume. Have constant volumen. Don´t have constant volumen.Don´t compress. They have difficulty compress. They compress easily.Don´t flow. They flow. They flow.

5.- Changes of state.

When matter changes from one state to another, there is what is known as a change of state. These changes of state can happen when bodies change their temperature or pressure. There are some changes of state:

Melting is when a solid turns into a liquid. For example, if ice is heated, it changes to water.

Solidification is the reverse transformation, when a liquid turns into a solid. For example, if water is cooled, it changes to ice.

Vaporization is when a liquid turns into a gas. There is two forms:

Boiling.- If the transformation happens a fixed temperature and quickly. When heat water comes a time in which begins to boil. There are big gas bubbles and vaporization occurs in everywhere of the water. This temperature is called boiling temperature. The boiling temperature of water is 100 ºC.

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Evaporation. It occurs at a lower temperature and is slower. For example, a pond water evaporates gradually until it dries, the clothes tend to dry out….

Condensation is the transformation of a gas into a liquid. For example, if water vapour is cooled, it changes to water. The classroom filled with steam in winter.

Sublimation is when a solid turns into a gas without passing through the liquid state. The reverse process, when a gas turns into a solid without passing through a liquid state, is inverse sublimation or deposition. For example, the naphthalene and iodine go directly from solid to a gas state.

Liquid water Solid water Water vapour

State changes occur by heating or cooling bodies. For example, the water becomes ice if cooled in the freezer and butter becomes liquid when heated in the oven.

The following chart summarizes changes of state:

Sublimation

Melting Vaporisation

S Solidification Condensation

Regressive Sublimation

6.- Physical and Chemical changes. Matter can undergo two types of change:

Physical changes .- They are those in which the substances of bodies don´t change. For example, when a glass bottle breaks into small bits, each of the bits is still glass. These are examples of physical change: changes of state, movement, fragmentation, dilation…..

Physical changes may be of two types: reversible and irreversible:

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Matter can exist in three states: solid, liquid and gaseous. When matter changes from one state to another, it undergoes a change of state.

SOLID LIQUID GAS

Reversible changes occur when the matter can recover its initial appearance. Stretching a rubber, for example, its length increases, and if we stretch it, retrieves its original form. The same applies to the cloth flags.

Irreversible changes occur when it is impossible to matter to recover its initial state. For example, if we make the wood sawdust

Wood Sawdust

Chemical changes .- Are those which produce a change in the composition of matter, producing new substances with different properties to that we had at the beginning. Combustion (when wood burns, turn on a match..), fry an egg, make bread, digesti food and fermentation (sugar turns into alcohol) are examples of chemical changes.

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A chemical change produce changes in the properties of the substances into different ones.

A physical change is a change in a property of matter without change its composition.

ACTIVITIES

1.- Looking for the meaning of the words in the dictionary:

a. Viscosity.b. Malleable.c. Fragile.d. Density.e. Opaque.f. Conductor.g. Waterproof.h. Transparent.i. Translucent.j. Strong.

2- Write the names of solids with these features:a) One hard and other soft.b) One very fragile and one that is not.c) Two very waterproof solids.d) One more dense than water.e) One less dense than water.

3.- Order from highest to lowest viscosity these fluids: honey, oil and water.

4.- Complete the box using the following properties: mass, temperature, color, solubility, density, volume, viscosity.

5-Completes the following examples of specific properties using the following words: boats, blankets, windows.

a) Transparency and the hardness of the glass take advantage to build................b) Wool is a good thermal insulator, and is used to make......................c) The fact that wood is waterproof and has lower density that water favouring use to

build........................

6.- What are the specific properties of the previous exercise?

MATTER PROPERTIES

General Specific

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7.- What phrases are general properties and what phrases are specifics properties?

a) It has a mass of 10 grams.b) It is shining.c) It is yellow.d) Its density is of 19,3 kg/L.

8.- Classifies the following list of substances according to the state in which they are: glass, wood, water, ice, oxygen, oil, blood, hydrogen, steel, gold and resin.

SOLID LIQUID GAS

______________________ ______________________ ______________________

______________________ ______________________ ______________________

______________________ ______________________

______________________ ______________________

______________________

9- Indicates several substances in your body that:

a) ... are solid state _____________________________

b) ... are liquid state _____________________________

c) ... are gas state _____________________________

10.- Write constant or variable.

a) Solids have ...................... volume and ..................... form.b) Liquids have ......................... volume and ......................... form.c) Gases have ………................. volume and ........................ forma.

11.- Complete the following table:

State Volume Form Compress FlowSolidLiquidGas

12.- Indicate if the following phrases are physical or chemical changes:

Melting ice. Fermentation of the wine. Combustion of butane in the kitchen.

Dissolve some sugar in a glass of water.

Evaporation a puddle of water.

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Oxidation of an iron bar. Dilation of a road train.

The solidification of the water. The photosynthesis.

13.- Indicate which the following physical changes are reversible or irreversible:

a) To break a paper.b) To freeze eater..c) To melt the chocolate..d) To dissolve an aspirin in water.

14.- Indicates in what cases a chemical change occurs:

a) We break a piece of cloth in pieces.b) We melt sugar for candy.c) We freeze water. d) We do react vinegar with bicarbonate and occurs much gas.

15.- What´s the difference between a physical and chemical exchange?

16.- Copy and complete the following diagram:

can be in three can undergo states changes

can be as

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Matter

Physical Chemical

© Manuel Blanco 2010

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