Properties of Matter. Matter Anything that has mass and takes up space Matter can take many forms and is not always visible to the eye Matter can change.

Properties of Matter

Matter

Anything that has mass and takes up space

Matter can take many forms and is not always visible to the eye

Matter can change form

Everything in the universe is made of matter

Energy, thoughts, feelings, ideas, sounds, light, heat, and emotions are not matter

Matter is made of atoms Matter can neither be

created nor destroyed; it just changes form - Law of Conservation of Matter

Atoms

Tiny particles that make up matter

They are so small that 1 million atoms lined up side by side are equal to the thickness of a human hair

“atom” comes from a Greek word that means “cannot be divided”

Atoms are the smallest unit of matter that has the identity of the matter

Atoms are in turn made of protons, electrons, and neutrons

Protons, electrons, and neutrons are called subatomic particles

Proton

Positively charged particle Located in the nucleus of an

atom

Electron Negatively charged particle Located outside the nucleus of

an atom

Neutron

Neutral particle, no charge Located in the nucleus of an

atom

Types of Matter - Elements

Most kinds of matter are made of combinations of a basic group of building blocks called elements

Element - matter made up of only one type of atom

There are about 116 different elements

Compounds

Compounds are matter made up of different kinds of elements, chemically bonded together

Compounds

When elements combine to make compounds, the new substance has properties that are different from the properties of the elements that made it.

Compounds

Na (sodium) is a very reactive metal and Cl (chlorine) is a poisonous gas

NaCl is table salt and tastes delicious on potato chips!

Chemical Formula Uses symbols and numbers to

represent the elements found in a substance and the number of each of those elements

Every element has a 1 to 3 letter symbol to represent the element, use the Periodic Table to match the symbol with the element

Chemical Formula - examples NaOH – Has 1 atom of Na (sodium), 1

atom of O (oxygen) and 1 atom of H (hydrogen) This is the formula for sodium hydroxide

C6H12O6 – Has 6 atoms of C (carbon), 12 atoms of H (hydrogen) and 6 atoms of O (oxygen) This is the formula for glucose.

Identifying Elements and Compounds

Elements and compounds can be identified by their properties

Scientists must do different tests to identify elements and compounds correctly

Identifying Elements and Compounds

It can take several tests and it helps to compare unknowns with known examples

Sometimes scientists also need to study the atomic and subatomic structures of matter to make a correct identification

Identifying Elements and Compounds

There is no simple test to tell whether a substance is an element or a compound

Properties

Characteristics or features of a substance

Substance – a general term for a compound or element (a fancy word for “stuff”)

Physical Properties

Characteristics of a substance that can be measured or observed without changing the identity of the substance

Physical Properties: examples

Size Shape Texture Color Density State of Matter (solid, liquid,

gas)

Physical Properties: Density Compares the mass of

something to how much space it takes up

Density = mass/volume To calculate density, divide the

mass of an object by its volume

Units for density: g/mL or g/cm3

Physical Properties: Density Density is a property that can

be used to identify a substance If you know the density of an

unknown substance, you can compare it to a list of densities of known substances and find a match

Link to a site with short lessons about density

http://www.middleschoolchemistry.com/multimedia/chapter3/lesson1

Physical properties: Solubility

Solubility – ability of one substance to dissolve in another (usually a solid in a liquid)

Soluble substances form solutions

Physical properties: Miscibility Miscibility – ability of one liquid

to mix with or dissolve in another liquid

Immiscible liquids don’t mix Less dense liquid floats on the

denser liquid

Chemical Properties of Matter

A characteristic of a substance that allows it to change into a new substance

Characteristics that relate to the atomic or elemental composition of substances

Chemical Properties of Matter – Examples Examples of chemical

properties: flammability (ability to burn),

ability to react with oxygen, reactivity (how easily one thing

reacts with another), or toxicity (how poisonous

something is)

Link to a site with short lessons about pH

http://www.middleschoolchemistry.com/multimedia/chapter6/lesson8

Lessons 8-10

pH pH is a scale used by scientists

to measure the acidity or basicity of a substance

pH 7 is neutral pH 1 up to pH 7 is acidic pH greater than 7 up to pH 14

is basic

pH pH is a chemical property pH is used to predict chemical

reactions or to select compounds for specific chemical reactions

Acids and bases are reactive compounds

Physical and Chemical Changes

Physical Changes

Any change in size, shape, form, or state of matter

The makeup of the matter stays the same, only the physical properties change

Examples of Physical Changes

Physical weathering Cutting or breaking something Change in state of matter

Changes in State of Matter Solid to liquid – melting Liquid to gas – evaporating

or boiling Gas to liquid – condensation Liquid to solid – freezing or

solidifying

Chemical Changes

Any change where one or more of the original materials changes into a new material

They can take place quickly or slowly (rusting)

Signs of chemical changes Heat or light can be released

Signs of chemical changes A new substance can be formed –

a gas is released, a solid or liquid forms

More signs of chemical changes Sometimes heat (energy) is

absorbed Sometimes a color change

happens

Link to a site with short lessons about chemical reactions

http://www.middleschoolchemistry.com/multimedia/chapter6/lesson1

Lessons 1-7