Unit B - Matter & Chemical Change

WHMIS

Workplace hazardous materials information system. This system gives us symbols that we can use to identify hazards

Danger Symbols:

Matter

Anything that has mass and occupies space. 3 types (In which matter can exist), solid, liquid, or gas

Changes in State

Properties Of Matter

Characteristic that describes a substance

Physical Properties of Matter

The physical appearance of matter
- color, shine (luster)
- melting temp, freezing temp, boilingtemp
- density, hardness, solubility, conductivity (ability to transferelectricity)
- malleability, ductility (ability to be hammered intothin sheets or made into wire withoutbreaking)

Chemical Properties of Matter

The way material behaves in a chemical reaction and reactions to other substances

Categorizing Matter

Pure Substance

Substance made up of one kind of matter

Element

Pure substance made of only one type of atom

Compounds

Chemical combination of two or more elements

Molecule:

Elements are held together via a molecular bond (Similar to compounds)

Heterogenous

Mixture in which the substances that make the mixture are visible

Homogenous

Mixture of two or more pure substances that looks like one substance

Suspension

Cloudy mixture where tiny particles of one substance are held within another and the particles can be separated out (Can be seperated through filtration, salad dressing)

Colloid

Cloudy mixture in which tiny particles of one substance are held within another but particles cannot be separated out from the other substance, milk)

Physical Change

Change in the appearance or state of a substance that doesn't change the composition of it

Examples of a physical change:

(Ex. Cutting, bending, dissolving, freezing, boiling, and melting)

How to know if a physical change has occured:

- You can separate the end products (reactants) to form the products again. Ex. Salt water, sand &rocks
- You are able to re-freeze or melt the product again. Ex. Ice cream, plastic mould
("reversible")

Chemical Change

Change that happens when 2 substances react to create other substances which results in completely different properties

Examples of chemical change:

(Ex. Change in color, burning, digesting, baking a cake)

How to know if a chemical change has occured:

- Change in color
- Change of odour (if present)
- Change of composition (ex. precipitate formed, gas released)
- Release or absorption of energy in the form of light or heat
(NOT "reversible")

CONTROLLING CHANGES IN MATTER TO MEET HUMAN NEEDS

Freeze-Drying Food - Food is frozen to ice to keep it from spoiling (Example of manipulating states of matter)

(8000 BC) Stone Age Chemists

Stone was used to make tools (Ex. Glass and ceramics)

(6000 BC - 1000 BC) Early Metal and Liquid Matter

Valuable metals were used (Gold, Copper)

(4500 BC) Bronze Age

Started using bronze (copper+tin) for weapons

(1200 BC) Iron Age

Middle easterners started extracting iron from rocks and produced steel

(400 BC) Democritus

Greek philosopher who believed that atoms (atomos: indivisible) were particles that could not be broken down further.

Aristotle

Well known and respected but his theory of everything on earth being made of earth, fire, wind and water was untrue

(350 BC) Alchemy

The earliest form of experimenting with chemicals to create new things (Half-Magician, Half-Scientist) (Also used scientific method)

Al Razi

Early alchemist who discovered changes in state of matter and how it worked (Plaster of Paris)

Andreas Libeau (German Alchemist)

Made the first chemistry text ever printed (1597)

Robert Boyle (Irish aristocrat, 1660)

Observed the nature of chemicals/Discovered gas properties and behaviour under pressure

Antoine Laurent Lavosier (French scientist with wife in 1770's)

Developed system for naming chemicals based on their interactions ("father of modern chemistry")

John Dalton

First modern theory of atomic structure (Billiard Ball)

J.J. Tomson (British Physicist, 1897)

First to discover subatomic particles (electrons), (Raisin Bun)

Hantaro Nagaoka (Japanese physicist, 1904)

Atom \= mini solar system

Ernest Rutherford (British Scientist, 1911)

Supported existence of a nucleus in atoms

Niels Bohr (Danish researcher, 1913)

Furthered the model of an atom where electrons do not randomly orbit but jump over shells and gain energy (electron orbit)

James Chadwick (British physicist, 1932)

Discovered the neutron (\=) and proton (+)

Structure of Atoms

(P.E.N) Protons (+) Electrons (-) Neutrons (\=)

The Atom

Centre: nucleus (contains protons and neutrons)
Surrounding the nucleus is the electron cloud.

Demitri Mendeleev

Russian chemist who created an organised system for the elements which correspond them with their patterns and properties (periodic table)

Dalton's Symbols

Dalton's symbols were created by John Dalton and were a way to organise elements and make corresponding symbols for them so that every chemist had the same system

Atomic Number

Shows how many protons (and electrons) are in the nucleus of one atom of the element

Atomic Mass

The mass of one atom of an element calculated from the total protons, neutrons and electrons of that atom. (Measured in amu - atomic mass units)
- (Subtracting protons from mass \= neutrons)

Period

A horizontal row of elements in the periodic table

Group/Family

A vertical column of elements in the periodic table

Metals

Shiny, malleable, ductile, conduct electricity

Metalloids

Have both metallic and non-metallic properties

Non-Metals

Solid (dull & brittle) or gases, don't conduct electricity (insulators)

Alkali Metals

A very reactive metal (Excludes Hydrogen)

Alkaline Earth Metals

Very reactive metals but not as reactive as Alkali metals

Noble Gases

An unreactive non-metal

Halogens

A very reactive non-metal

Isotopes

These are atoms of the same element but have different numbers of neutrons in the nucleus. Their mass numbers will be different but atomic number is the same

Transition Metals

Group 3 to group 12 metals that are found in the middle of the periodic table. They all have similar properties.

Atoms strive to:

Be stable (Filling up electron shells appropriately)

Chemical Formula

Chemical Formula is a series of symbols which identify how many and which elements are a part of a compound. {Ex. HF(g)}

Naming Chemical Compounds

Organises and show what elements belong in each compound and how many there are. (The metal element always goes first)

Ionic compound

Pure substance formed when at least one metal and one non-metal combine/attraction between tewo oppsitely charged atoms
- 1st element: Metal (Full name)
- 2nd element: Ends in "ide"
(NO PREFIXES)

Ions

Atoms that have become electrically charged because they have lost or gained electrons.

How do ions balance?

+ ion \= atom that has lost one or more electrons
- Ion \= atom that has gained one or more electrons)

Cation:

A positively charged ion that has lost electrons

Anion:

A negatively charged ion that has gained electrons

Polyatomic Ions:

A group of atoms acting as one

Monatomic Ions:

An individual atom that has a positive or negative charge

Ion Charge

Ion charge is whether an atom of a specific element would have a positive or negative charge.

Molecular Compound (Covalent)

Pure substance formed when nonmetals combine/when two or more atoms share electrons
- 1st element: Non Metal (Full name)
- 2nd element: Ends in "ide"
(ENDS IN PREFIXES)

Naming Molecular Compounds

Naming Molecular Compounds is assigning a prefix to each element to show how many elements of each there are. (Ex. Dinitrogen trioxide - N2O3)

Chemical Reaction

A reaction that takes place when two or more substances react to form new substances

Reactants

A substance that reacts (with other substances) in a chemical reaction to create new substances with different properties (appear to the left of the arrow in a chemical equation)

Products

A new substance produced in a chemical reaction between reactants (appear to the right of the arrow in a chemical equation)

Chemical Word Equations

Chemical Word Equations represent a chemical reaction using the full names of the substances used. (Ex. Wood + oxygen → carbon dioxide + water + energy released)

Endothermic

A chemical reaction that absorbs heat energy. (Ex. Reactants in cold packs being crushed together)

Exothermic

A chemical reaction that releases heat energy. (Ex. Your body metabolising food)

Combustion

A chemical reaction that occurs when oxygen reacts with a substance to form a new substance (it gives off energy) Fuel (ex. wood) + oxygen → carbon dioxide + water

Corrosion

A slow chemical change that occurs when oxygen in the air reacts with a metal (Metal (ex. iron) + oxygen → rusted iron)

Cellular Respiration

A chemical reaction that occurs in cells. The food reacts with oxygen to produce energy, water, and carbon dioxide (Food (ex. glucose) + oxygen → carbon dioxide + water)

Conservation Of Mass

Conservation of mass is a principle that states that in a chemical reaction, matter isn't created or destroyed. (Mass of products \= mass of reactants) (Ex. combining 24.3 g of magnesium and 32.1 g of sulphur creates 56.4 g of magnesium sulphide)

Closed System

An experiment where all reactants and products in a chemical reaction can't enter or leave

Open System

An experiment where one or more products of a chemical reaction can escape

Catalysts

Substances that help to speed up a reaction (Present, but not consumed)

Enzymes

A catalyst involved in chemical reactions in living things

Temperature

A factor that affects the rate of a reaction. If you increase the temperature of the reactants, the reaction will act faster. This means the atoms move around quickly in the reactants due to the temperature.

Concentration

A factor that affects the rate of a reaction. If you increase the concentration of the reactants, the reaction will act faster. This means there are more reactant atoms available to react.

Surface Area

Surface Area is also a factor that affects the rate of a reaction. If you increase the surface area of the reactants you will have a greater number of reactants so that more area is available for reaction.

Qualitative:

Relating to, measuring, or measured by the quality of something rather than its (quantity)

Quantitative:

Adding to, measuring, or measured by the quantity of something rather than its (quality)

Emulsion:

Any mixture of two or more immiscible liquids in which one liquid is dispersed in the other

Each atom has an equal number of:

Protons and electrons

Diatomic molecules:

molecules made up of two atoms of the SAME element

Binary compound:

a compound composed of two DIFFERENT elements

Prefixes:

1 - Mono
2 - Di
3 - Tri
4 - Tetra
5 - Penta
6 - Hexa
7 - Hepta
8 - Octa
9 - Nona
10 - Deca

Inhibitor:

A substance that slows down or stops a chemical reaction