Intro. to Chemistry

What is Chemistry?

• The study of the composition and changes of matter.

•What is Matter?–All living and nonliving things–Anything with mass–Anything that takes up space

•What isn’t Matter?–Energy (light, waves, etc)

• Areas of Study• Organic Chemistry ––The study of all chemicals containing

carbon.–Ex. Living things

• Areas of Study• Inorganic Chemistry–The study of chemicals that do

NOT contain carbon.–Ex. Studying rocks (non-living)

• Areas of Study• Biochemistry–The study of the chemical processes

that take place in organisms–Ex. Muscle contraction and digestion.

• Areas of Study• Analytical Chemistry–The area of study that focuses on the

composition of matter.–Ex. Amount of lead in drinking water.

• Areas of Study• Physical Chemistry–The study that deals with the

mechanism, the rate, and the energy of chemical changes.

How do we describe matter?

• Matter has extensive properties.• Extensive properties are properties that

depend on the amount of matter in a sample.– Examples:• Mass• Volume• Length

• Matter has intensive properties.• Intensive properties are properties that depend on

the type of matter in a sample, NOT the amount.– Examples:

• Hardness• Shape• Luster• Malleability• Ductility• Conductivity• Melting/Freezing Point• Color• Odor

• Matter has physical properties.• Physical properties identify the substance

without changing it.– Examples:• Physical State (solid, liquid, gas)• Color• Melting Point• Boiling Point

• Matter has chemical properties.• Chemical properties identify the substance as it

chemically reacts.– Examples during a reaction:• Rusting• Burning• Odor given off• Temperature change

• Matter can go through physical changes.– Change where type of substance does not change.– Reversible changes (sometimes irreversible)– Examples:• Changes of state• Changes of shape• Changes of texture• Breaking

• Matter can go through chemical changes.– Changes where material becomes a new substance– Involves a chemical reaction– NOT usually reversible – Always involve reactants and products– Include processes such as: burning, exploding,

rusting, corroding, fermenting, rotting– Evidence of chemical changes:• Energy transfer• Gas production• Precipitate• Change of color

Chemical Reactions Conserve Mass

• Law of conservation of mass - in chemical reactions mass is not created nor destroyed

• Mass of reactants = Mass of products

•CH4 + 2O2 CO2 + 2H2O

Classifying Matter

• Matter can be classified as either a mixture or a pure substance.

Mixtures

• Heterogenous mixture: not uniform– Example: soup, salad dressing

• Homogenous mixture: uniform– Homogenous mixtures are also known as

solutions.– Examples: air, steel, nickel

– Solution Examples:• Salt water• Beer• Pop

• Mixtures are only physical combined.• We can separate them by the following:– Filtration-separate by size or state– Distillation-separated by boiling point

Classifying Matter

• Elements:– Metals– Nonmetals– Metalloids

Classifying Matter

• Compounds and Molecules:– Substance that contains 2 or more elements

chemically combined in a fixed ratio.

• Memorize common elements.• Memorize the 7 diatomic molecules.