PHYSICAL SCIENCEJONES

Chapter 2: Matter

Good Morning!

Please find a partner and a book to share.Get out one sheet of paper and something to

write with.Open to page 38.

Get To Know Your Vocab!

On a sheet of paper, draw 6 of these:

Definition

Examples

Characteristics

Non-examples

Vocabulary Word

Get To Know Your Vocab!

For each of the diagrams, write the vocab word and its definition. We will discuss characteristics, examples, and non-examples.

1. Atom2. Molecule3. Element4. Compound5. Pure Substance6. Mixture

Atom

Characteristics: All atoms of an element are identical in properties Atoms are composed of protons, neutrons, and electrons Atoms of different elements can combine to make compounds Atoms cannot be broken down any further

Examples: An atom of hydrogen An atom of oxygen An atom gold

Non-examples: A molecule of water A molecule of air A molecule of salt

Molecule

Characteristics All molecules of a compound are identical in properties Molecules are composed of atoms of 2 or more elements Molecules can be broken down into individual atoms of

elementsExamples:

A molecule of sugar A molecule of carbon dioxide A molecule of water

Non-examples: An atom of sodium An atom of silver An atom of helium

Element

Characteristics: All elements can be found on the periodic table Each element is composed of identical atoms Elements can combine to produce compounds Each element is classified as a metal, nonmetal, or metalloid

Examples: Sodium Potassium Chlorine

Non-examples: Water Salt Air

Compound

Characteristics: All compounds are composed of 2 or more elements Compounds consist of identical molecules Compounds can have different properties than the

elements they are made ofExamples:

Salt (sodium chloride) Water (H2O) Glucose

Non-examples Carbon Steel Italian dressing

Pure Substance

Characteristics: The composition of pure substances will never change The properties of pure substances will never change Pure substances can be mixed to produce mixtures Pure substances cannot be separated physically

Examples: Any element Any compound

Non-examples: Salt water Sweet tea Steel Italian dressing

Mixture

Characteristics: Mixtures have various amounts of their components Mixtures are produced by mixing pure substances

together Mixtures can be separated physically

Examples: Grape juice Air Chicken noodle soup

Non-examples: Any element Any compound

What is matter?

Matter: Anything that has mass and takes up space Examples: your desk, air Non-examples: sound, light

All matter is composed of atoms and molecules

Element Symbols and Chemical Formulas

Element symbols Represent elements Are found on the periodic table ONE capital letter, and sometimes one lowercase letter

Na O Fe

Chemical formulas Represent compounds Two or more element symbols put together AT LEAST TWO capital letters, and sometimes small numbers

called subscripts H2O NaCl C6H12O6

Chemical Formulas

The subscripts represent how many atoms of that element are in the compound

How many atoms of each element are there in C6H12O6?

Chemical Formulas

The subscripts represent how many atoms of that element are in the compound

How many atoms of each element are there in C6H12O6? 6 Carbon atoms 12 Hydrogen atoms 6 Oxygen atoms

Chemical Formulas

How many atoms of each element are in (NH4)2SO4?

Chemical Formulas

How many atoms of each element are in (NH4)2SO4?

2 Nitrogen atoms 8 Hydrogen atoms 1 Sulfur atom 4 Oxygen atoms

Mixtures

Can be divided into two groups: Heterogeneous – substances aren’t evenly mixed

Flour + water mix to form a cloudy white mixture Oil + water may mix temporarily but will eventually

settle out

Homogeneous – components of the mixture are evenly distributed Gasoline Sugar-water mixture

Mixtures

Can you think of any examples where a gas is mixed in a liquid?

Mixtures

Can you think of any examples where a gas is mixed in a liquid? Soda

Gas is not dissolved in the liquid, but is mixed in As the gas bubbles rise to the surface of the soda, they

can escape into the atomsphere Once all the bubbles from the mixture have escaped, you

have flat soda! Meringue (for use in pie)

Egg whites are whipped with enough air to produce foam The foam is baked in the oven to solidify, to produce

meringue

Properties of Elements and Compounds

Properties that describe a certain substance are either physical or chemical Physical properties are characteristics that describe

the appearance of that substance Color Shape Melting point/boiling point

Chemical properties are characteristics that relate a substance’s ability to undergo changes that transform it into different substances Ability to burn Ability to rot or decompose

Physical Properties

Describe matter Shape Color Odor Texture State of matter (solid, liquid, or gas)

Physical Properties

Can be constant for certain substances Melting point Boiling point Freezing point Density

How much matter is contained in a certain volume of substance

Density = mass/volume Unit: g/cm3 or g/mL Unit for mass: grams, Unit for volume: cm3 or mL

Chemical Properties

Describe how a substance reacts Reactivity

Ability to react with oxygen, acid, water, etc. Flammability

Ability to burn Other examples

Ability to rot Ability to rust

Changes in Elements and Compounds

A change in a substance can either be described as physical or chemical. A physical change does not change the composition of

that substance. Melting/boiling Change of state (solid liquid gas) Breaking/tearing

A chemical change occurs when one or more substances are converted into different substances Burning Rusting Rotting

Physical Changes

Do not change a substance’s identityExamples:

Dissolving Cutting Sanding Crushing Breaking Tearing Changing state of matter (solid liquid gas)

Chemical Changes

Occurs when one or more substance changes into entirely new substances with different properties

Examples: Baking a cake! Iron rusting Milk souring

Signs of a chemical change: Color change Production of gas Production of precipitate Production of energy in the form of heat or light

Separating Mixtures

Mixtures can be separated physically Straining Centrifugation Distillation

When are reactions reversible?

Some physical changes are reversible, some are not Dissolving a substance, then using distillation techniques to

separate the components

Some chemical changes are reversible, some are not You cannot “unbake” a cake When water is formed, it can be split back into oxygen and

hydrogen

A double arrow represents a reversible reaction A + B C + D