Origins And Distribution of Elements Organizing Matter

I can distinguish between pure substance, elements, and mixtures. Objective I can distinguish between pure substance, elements, and mixtures.

Chemistry Chemistry is the study of matter and the changes it undergoes

Matter: anything that occupies space and has mass

What is Matter Made of? Matter is composed of atoms and atoms make up molecules Atoms: submicroscopic particles that are the main building blocks of matter Molecules: two or more atoms joined together

How is Matter Organized? Matter can be divided into two categories Pure Substances Mixtures

Pure Substances Pure substance: composed of only one type of atom or molecule Example: gold – all the atoms that compose gold are all gold atoms

Pure Substances Pure substances can be divided into two categories: Elements Compounds

Element: a substance that cannot be broken down into smaller substances and contains only one type of atom All known elements are listed in the periodic table Elements

Elements Chemists use symbols of one or two letters to represent the elements The first letter of the symbol is always capitalized the other letters are lowercase

Compounds Compound: two or more different elements chemically bonded together They can be broken down into simpler substances Example: water can be broken down into hydrogen and oxygen Compounds can be separated only by chemical means

How is matter organized? Matter can be divided into two categories: Pure Substances Mixtures

Mixture Mixture: a combination of two or more substances in which the substances retain their distinct identities Examples: soil and mixed bag of candies A mixture can be created and then separated by physical means into pure components

Mixture Mixtures can be divided into 2 categories: Heterogenous Mixtures Homogeneous Mixtures

Mixture Heterogenous Mixture Homogeneous Mixture Heterogenous mixture: the composition is not uniform Example: bowl of cereal Homogenous mixture: the composition of the mixture is the same throughout Example: salt water, grape juice

The Properties of Matter Properties: characteristics that distinguish one substance from another Example Properties: color, melting point, boiling point Different substances have unique properties

The Properties of Matter Physical Property Chemical Property Physical property: a property that can be measured and observed without changing the composition or identity of a substance Odor, taste, hardness, texture, color Example: water differs from ice only in its appearance, not composition Chemical property: a property that must carry out a chemical change to be observed Flammability, rusting, tarnishing Example: burning hydrogen gas turns it into oxygen gas and water, after the chemical change the substance (hydrogen gas) will have vanished

The Properties of Matter What is an example of a physical property of a candle? What is an example of a chemical property of a candle?

Three States of Matter A change in state is a physical change All substances can exist in three states: solid, liquid, and gas A change in state is a physical change States of matter differ in the distances between the molecules

Solid The atoms or molecules are packed close to each other in fixed locations, can vibrate but do not move Solids have a fixed volume

Liquid The atoms or molecules are close to each other but they are free to move around Liquids have a fixed volume

Gas Gas – molecules are separated by large distances The large distances allow molecules to move Because they are not in contact with one another they are compressible Not a fixed volume