Ch 2: Nature of Matter

What is Matter?

matter is anything that has mass and volume

Substance is pure matter made of only one type of particle

Matter has Volume

Volume: the amount of space that matter takes up

Volume

rectangular solid with regular sides, Use the formula Volume = l x w x h

Label your answer with Cubic centimeters or cm3 or CCs

• solids with irregular sides: use displacement method:

• Fill a graduated cylinder with water, add the material and measure how much water is pushed out of the way

• Label your answer using cubic centimeters or milliliters

volume

Liquids: measured with a graduated cylinder

Label your answer in liters or milliliters

volume

Gas: measure the size of the container

Label your answer using cubic meters or cubic centimeters

• Mass is the amount of matter in an object

• Mass is measured with a balance using grams as the base metric unit

mass

MATTER HAS DENSITY

• Density is: the amount of matter in a given space.

• Density is calculated: Density = Mass

Volume

density

Density is measured with a balance (for mass) and a graduated cylinder (for volume)

Label your answer with the metric units g/ml or g/cm3

• Water’s density is 1g/ml or 1 g/ cm3

• Every pure substance has its own density, density is a characteristic property used to identify a substance

density

MATTER CAN BE DESCRIBED BY ITS PROPERTIES.

• A property is a characteristic used to describe an object.

•Both chemical and physical properties are used to identify and describe matter

1. Physical property - a characteristic of a pure substance that can be observed without changing it into another substance

2 types of properties

Examples of physical properties:

• color• taste• odor• volume • mass• density

viscosity solubility melting point boiling point Electrical conductivity thermal conductivity

•Chemical property - a characteristic of a pure substance that describes its ability to change into a different substance with new properties

Chemical property

Examples of chemical properties:

Ability to rust Ability to tarnish Flammable Reacts with baking soda Reacts with acids Reacts with bases

Matter can be identified by its properties that do not change even when the sample size changes.

Some of these properties are: density, melting point, boiling point, and what it reacts with.

Elements:

Elements are pure substances made up of only one type of atom. They cannot be broken down into a simpler substance

There are about 115 known elements, 92 natural Rest are man-made

element

Each element has its own atomic structure and a unique set of physical and chemical properties that identify it

the smallest particle of each element is the atom

Compounds

a pure substance composed of two or more elements

chemically combined in a set ratio smallest piece of a compound

is called a molecule.

compounds

Most elements in nature are combined with other elements

most substances we use everyday are made of compounds.

compounds

When elements are chemically combined they form compounds with properties that are DIFFERENT from the original elements

compounds

Compounds can be chemically broken down into the individual elements that form them

Examples of property changes

Water – clear liquid formed from two highly explosive gasses

Table salt – white crystalline solid necessary for cellular function formed from an explosive silvery metal and a poisonous green gas

compounds

Chemical formula - Compounds combine according to certain ratios, there is a set “recipe” Ex: water is ALWAYS 2 hydrogen

atoms bonded to 1 oxygen atom

Mixtures

A mixture is 2 or more substances PHYSICALLY combined

Each substance keeps its original physical properties

mixtures

Parts of a mixture can be separated by PHYSICAL changes

Substances in the mixture can be any amount in the mixture (no set “recipe”)

Heterogeneous mixtures have particles big enough to see, they are not evenly mixed and some particles are big enough to separate out.

2 kinds of mixtures

2 kinds of mixtures

Homogeneous mixtures look the same throughout, they are evenly mixed and do not separate on their own.

Solutions a homogenous mixture with the smallest

particle size Concentrated – a lot of one substance

dissolved in another. Ex. Very salty salt water

Dilute – not very much of one substance dissolved in another

Ex. Not very much salt in salt water

matter

elements compounds

mixtures

heterogeneous homogeneous

atoms

molecules

Matter can change in two ways

Physical change: a change in form or appearance, but no new substance is created; most physical changes are easy to undo.

Examples of physical change Change of State: solid to a liquid;

liquid to a gas, etc. Change in form or shape dissolving salt in water bending metal crushing breaking

Chemical change

a change that occurs when one or more substances are changed into entirely different substances with new properties

Examples of chemical changes

Souring milk, bubbling or Fizzing when 2 things

combine, Iron rusting, Bleach taking color out of

something Burning

Conservation laws Law of Conservation of Matter -

Matter is not created or destroyed in any chemical or physical change

Law of conservation of energy- Energy is neither created nor destroyed, but can change forms

Energy

Energy – ability to do work or cause change. Like matter, energy is never created or destroyed in chemical reactions, it can only be transformed (changed from one form to another)

energy

Thermal energy – total energy of all of the particles in an object

Temperature – measure of the average energy of random motion of particles of matter

energy

Endothermic change – a change in which energy is taken in. Ex: melting ice

Exothermic change – a change in which energy is released. Ex: combustion – heat and light are produced.

energy

Chemical energy – energy stored in chemical bonds between atoms, energy stored in the foods you eat, gasoline to fuel a car, etc.

Electromagnetic energy – energy that travels through space and waves. Ex: radio waves, microwave oven, etc.