Classification of Matter

The Particle Model (Theory) of Matter

All matter is made up of extremely tiny particles called atoms

2. Each pure substance has its own kind of particles, different from the particles of another substance

3. Particles of matter attract each other

4. Particles are always moving

5. Particles at a higher temperature move faster than average particles at a lower temperature

The particle model helps us to understand the nature and properties of matter Matter can be classified by its state: solid, liquid, gas or plasma. Matter can also be classified according to its composition as mixed or pure substance

Matter You are surrounded by matter. EVERYTHING is made up of matter. Matter – anything that has mass and takes up space. It can exist in all three states.

You Try! How would you separate the following mixtures? Sugar and water and sand Table salt, iron filings and aluminum filings

Properties of Matter Properties – are characteristics that can be used to describe a substance Physical Property – a property that a substance has on its own. It can be observed without changing the substance into something else Ex Describe your friend.....you may talk about their height, weight, hair color, eye color

Chemical Property – a property that can only be observed when the substance changes into another substance. Ex – flammability, does it tarnish (change color) when exposed to air, change in color, smell, temperature

Physical Properties Shape/color State at room temperature Density (how hard it is) Melting point/boiling point Is it magnetic? Conductivity –will it conduct electricity? Solubility – can it dissolve? Malleability – can it be beaten? Flattened? Ductility – can it be stretched into wires?

Chemical Properties Change in smell (odor) Change in color How does it react with air? Rusting Flammable Reaction with acids Reaction with water Reaction to heat

Physical VS Chemical Changes Change in the appearance of a substance that does NOT change the chemical composition of the substance Ex ice ceam melting, bedning metal, crushing a sugar cube, making Kool Aid

Involves energy transfer (change in temperature) ____________ Changes Change that results when two or more substances react together to create a new/different substance The new substance has completely different properties from the original ones (NOT just change in state!) Involves energy transfer (change in temperature) Ex cooking pancakes

Evidence of Chemical Changes H C P I G

You Try! Identify the physical and chemical properties in this sentence: “Iron is very magnetic, it has a tendency to tarnish in air, and bubbles when placed in hydrochloric acid Work on the chemical and physical part of the worksheet, Review of Matter

Heterogeneous mixtures have particles that are not uniformly scattered and appears as two or more substances mixed together

Homogeneous mixtures have particles that are uniformly scattered and the mixture appears to be ONE substance It is impossible to tell a solution from a pure substance by appearance ALONE

Hetero/homogenous?

If.....Than..... If heterogeneous mixtures disperse the beam of light as it refracts/reflects off the particles, then.. Question: what type of lights should you use in heavy fog? High Beam Low Beam No Lights Why?

Pure Substances and Mixtures Pure Substance – matter that has a definite composition. Therefore it can be an element, or a compound. All parts are the same. Al, Cu, O H2O, NaCl, CO2 Mixture – a combination of matter that can be separated by physical means and dose NOT have a definite composition

Difference between Mixtures and Pure Substances You MAY be able to tell them apart by smell, texture, or density (physical properties) Or you may need to examine the melting point, boiling point etc. (chemical properties) Mixtures boil and freeze at different temperatures than the pure substances that make them up! Ex. Adding salt to the roads in winter LOWERS the melting point of the ice, so it melts quicker

You Try! A black solid with a constant melting point is heated to a high temperature, producing a gas and a shiny metal. The boiling point of the gas is -183oC and the melting point of the metal is 1085oC. IS the black solid and element, compound or mixture? Explain

Breakdown Constant melting melting point means it is not a mixture. (it would change if different substances were in the substance) Both a blue gas and a solid are formed from the original black solid, so it is NOT an element (which would have been pure) Compound!

Is this 100% pure juice?

Elements and Compounds

Elements and Compounds A compound – a pure substance composed of two or more elements combined together in fixed proportions (ratio) An element – a pure substance with definite composition made up of one type of atom

1) Mechanical (Ordinary) Mixtures Each part is big enough to be seen The parts stay mixed Example: granite You can see the quartz, Feldspar and mica

2) Suspensions Heterogeneous mixtures made up of large particles that are uniformly mixed Particles will settle if left undisturbed CAN be seperated by filtering WILL scatter light Examples: flour, charcoal, powdered chalk

3) Colloids Heterogeneous mixtures made up of fine particles evenly distributed Ex. Hair gel, clouds Tyndall Effect – the scattering of light by colloidal particles

4) Emulsions A type of colloid in which liquids are dispersed in another liquid The molecules can separate to form layers of the original liquids Adding an emulsifying agent may keep the liquid dispersed in the other liquid Example: peanut butter, or mayonnaise