Chemistry/1 Definition of matter Unit 1

Mixture

-Anything made of more than one type of particle -Properties of a mixture are a combination of the properties of each substance

Atomic Theory of Democritus

-Greek philosopher, 400 BC -Named the smallest pierce of matter "Atomos" meaning not to be cut ( the smallest pieces of matter) -Democritus atoms were small, hard particles that were made of the same material but different sizes -Atoms were infinite in number always moving and capable of joining together.

pure substance

-Made of one kind of particle -Have a set of fix properties It can be a : Compound Molecule Element(atom)

Law of Conservation of Mass

-Matter can neither be created or destroyed -Mass always stays the same in a closed system regardless of the type of change taking place

Melting Ice

-Particles went form solid to liquid -Still water (same substance as ice) -Still same number of particles because the mass did not change -PHYSICAL CHANGE

periodic table

-Periodic table lists every type of atom that exists in nature -The element iron is made of iron atoms -Example: The element sulfur is made of sulfur atoms -Elements are made of 1 type of atom -Each atom/element has its own unique properties

Properties of mixtures

-The properties of the substances (components) are retained.

diatomic elements

-There are 7 elements that can not exist by themselves -Can combine with other elements to form compounds -As pure elements they are always diatomic (2 atoms/molecule) -Diatomic elements can exist by alone. It must pair with same atom or other atoms. The 7 diatomic elements- HOFBrINCl: H2 Hydrogen N2 Nitrogen F2 Fluorine B2 Bromine I2 Iodine N2 nitrogen Cl2 Choline

chemical change

-a change that produces matter with a different composition than the original matter -A change in a substance that involves a change in identity or chemical makeup of the substance -All chemical changes are accompanied by a physical change. - Not easily reversed -new particles form -Often heat, light, sound, fizzing occurs EX: Wood Burning

Displacement method of measuring volume

1- Add water to a measuring cup such as graduated Cylinder. Record the volume of the water 2. Place an object in the water in graduated cylinder. Measure the volume of the water with the object in it 3. Subtract the first volume from the second volume. The difference represents the volume of the object

pure substance vs mixture substance

A Pure substance is made of only one type of particle. Has a set of fixed properties. Can be a Compound molecule atom (element) Mixture-Made of more than one one type of particle. Properties of the mixture are the combination of the properties of each substance. Can be : Homogeneous heterogeneous

Compound

A combination of 2 or more DIFFERENT types of atoms held together by a chemical bond (chemical change)

Mixture

A combination of two or more substances that are not chemically combined.

Element

A pure substance made of only one kind of atom

Chromatography

A technique that is used to separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of another material. Disproves Democritus's model that substances are made of only one kind of atoms Substances are made of a mixture of different atoms-not just one

Elements families in the periodic table

Alkali metals- very reactive, soft, do not occur freely in nature Alkaline earth metals- reactive, do not occur freely in nature Transition metals- some magnetic, more stable than alkali and alkaline metals Inner Transition metals - many are highly unstable or radioactive Halogens- form salts, exist in all three sta

Example of density:

Aluminum and Cooper (two identical cubes) -Copper atoms are smaller that aluminum -More Copper atoms can fit in the cube -Copper atoms are also heavier than aluminum atoms -The combination of more and heavier atoms make the Copper more dense that aluminum Differences in density between metals are usually based on -Size and mass of the atoms

Matter?

Anything that has mass and takes up space (volume) (MATTER IS ALL THE STUFF IN THE UNIVERSE) -All matter composed of atoms particles which are indivisible

Density

Density = mass/volume Describes the amount of stuff (mass) within a defined space (volume Example : in the attached picture, both boxes are equal in volume but the one on the right would have a higher mass and density.

Homogeneous mixture

In a homogeneous mixture, it isn't possible to see the different substances. Mayonnaise is a homogeneous mixture. It contains oil, eggs, and vinegar, but we can not see this individual ingredients. Although we can not see them, it is sometimes possible to separate the individual substances.

Techniques to separate mixtures

Manual separation Magnetic Attraction: Magnetic materials from non-magnetic materials Filtration: A solid from a liquid Crystallization: A solid from a solution Distillation: A solvent from a solution Chromatography: Different substances from a solution Solvent Extraction: A component from a mixture with a suitable solvent -Water Dissolves dome salts or sugars -White spirits: dissolves paint -Propanone: Dissolves grease, nail polish -Ethanol: Dissolves glues, printing inks, and scented substances

Ways we can measure matter

Mass - the amount of matter (atoms) something has Measured using an electronic scale Units: grams (g) Volume - the amount of space something takes up Measured using a graduated cylinder or taking the dimensions (length, width, height) Units: milliliters (mL) or cubic centimeters (cm3)

Separating Particles from mixtures and compounds

Mixture Particles in a mixture can be separated without chemical change but instead by physical means Methods: filtration, distillation, magnet, chromatography, centrifuge Compound Atoms in a compound can only be separated by chemical change Breaks chemical bonds between atoms Example) When we used electrolysis to split water into hydrogen and oxygen

Molecule

Pure Substance Any combination of two or more atoms (same or different) held together by chemical bound -the atoms can be the same or different.

Centrifugation

Separates components by density using high speed spinning

particle

Smallest piece of matter. Can be -A molecule-any chemical combinations of atoms (same of different) -an atom- an indivisible particle

Types of mixtures

homogeneous and heterogeneous

phases of matter

solid- -Fixed volume and fix shape -Do not take the shape of the container -particles are in order and fix arrangenments liquid- -Fixed volume indefinite shape -Take the shape of the container -Particles flow pass each other -particles are not in order gas- -Particles are separated -floating -take the volume are shape of the container

physical change

a change of matter from one form to another without a change in chemical properties -no new particles formed -often just a state -easily reverse EX: Ice melting ALL CHANGES IN STATE OF THE MATTER ARE PHYSICAL CHANGES FOR EXAMPLE: Solid to liquid liquid to gas gas to liquid

Volume

The amount of space an object takes up

Heterogenous mixture

We can see the individual substances that make up a heterogenous mixture. This means that it is possible to separate the substances easily- a fruit salad is a heterogeneous mixture.

More on Compounds

When elements forms compounds they take on completely different properties