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Chemistry
Page One Title

Topic 1:  Matter and Energy

[ Home ] [ Topic 1:  Matter and Energy ] [ Topic 2:  Atomic Structure ] [ Topic 3:  Periodicity ] [ Topic 4: Ionic and Covalent compounds ] [ Topic 5:  Chemical Equations ] [ Topic 6:  Stoichiometry ] [ Topic 7:  Causes of Change ] [ Topic 8:  Gases and Condensation ] [ Topic 9:  Solutions ] [ Topic 10:  Acids and Bases ] [ Topic 11:  Electrochemistry ] [ Topic 12:  Nuclear Chemistry ] [ Bibliography ]

a)  What is matter? (Properties, descriptions, examples)

    Matter is anything that has mass and volume.  The properties of matter are color, mass; volume, texture, transparency, flammability, and taste are a few of the many properties of matter.  Color, texture, shape, and mass can be observed or measured without changing the composition of matter.  Properties such as these are called Physical Properties.  States of matter are solid, liquids, and gases are the three states of matter.

Making Matter.

3D picture of 

matter.

 

 

 

Main Properties of matter are:

Property

Description

Example

Electrical conductivity

Ability to carry electricity

Copper is a good electrical conductor, so it is used in wiring.

Heat conductivity

Ability to transfer energy as heat

Aluminum is a good heat conductor, so it is used to make pots and pans.

Density

Mass-to-volume ratio of a substance; measure of how tightly matter is Packed

Lead is a very dense material, so it is used to make sinkers for fishing line.

Melting Point

Temperature at which a solid changes state to become a liquid

Ice melts to liquid water at the melting point of water.

Boiling point

Temperature at which a liquid boils and changes state to become a gas at a given pressure

Liquid water becomes water vapor at the boiling point of water.

Index of refraction

Extent to which a given material bends light passing through it

The index of refraction of water tells you how much light slows and bends as it passes through water.

Malleability

Ability to be hammered or beaten into thin sheets

Silver is quite malleable, so it is used to make jewelry.

Ductility

Ability to be drawn into a thin wire

Tantalum is a ductile metal, so it is used to make fine dental tools

b) How do matter and energy interact?  (Forms of energy, how mass and energy relate, how matter changes)

    We know that Energy plays a big row in Chemistry.  Energy is a broad concept, but a good basic description is that energy is the capacity to move or change matter.  Two energies play a big row in how matter and energy interacts.  Kinetic Energy:  energy that moving objects posses by virtue of their motion.   The other kind of energy is called Potential Energy:  is energy an object possesses because of its position.  Those are the two main kinds of energies that matter interacts with.

    An example of kinetic energy is the kinetic energy of a cheetah chasing its prey can be calculated if you know the cheetahs velocity and mass.   To find out the kinetic energy you can use the following formula.

                 KE = (1/2)mv2 

  • KE = Energy (in Joules)

  • m = mass (in kilograms)

  • v = velocity (in meters/sec)

cheetah-10.jpg

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An example of potential energy is if you have a trampoline and before you jump on it, it is neither stretched nor compressed.  When the trampoline is compressed which gives it potential energy.  Then when the potential energy decreases it sends you flying up into the air.  When the trampoline is stretched it gives it potential energy.  Then when I move back and forth to make you fly it potential energy decreases.

c) How is matter classified? (Mixtures and pure substances, elements, compounds)

      Matter can be classified as either a pure substance or a mixture.  A pure substance is matter made of only one kind of atom or molecule.  Carbon dioxide, hydrogen, and copper are all examples of pure substances.  A mixture is a collection of two or more pure substances physically mixed together that cannot be represented by a chemical formula.  Mixtures can be classified as heterogeneous or homogeneous.

    A Homogeneous Mixture is one in which the substance are uniformly distributed.  Gasoline, syrup, and saltwater are homogeneous mixtures.  Homogenous mixtures that consist of substances mixed on the scale of individual particles are called solutions.  Gasoline, tea, and saltwater are all solutions, for example. 

   A Heterogeneous Mixture is a mixture that can take many forms.  For example water mixed with oil and oil with vinegar are two-phase, heterogeneous mixtures.  Elements are the simplest pure substances because they contain only one kind of atom.   Compounds are two or more different elements that are chemically combined.