Lesson 1 (Scientific Method, Classifying Matter, Physical and Chemical Properties and Changes)

Chemistry

 The study of composition, properties, and interactions of matter

Matter

Anything that has mass and occupies space (takes up volume)

Chemicals

Substances that always have the same composition and properties (they are all around you)

Natural Chemicals

Found in nature and produced without human intervention

Exampes of Natural Chemicals include:

Caffeine, citric acid, and penicillin (mold)

Synthetic Chemicals

Made by humans, starting substances are changed chemically to produce a material with different characteristics

Examples of Synthetic Chemicals include:

Aspirin, food dyes, and plastics

Inorganic Chemistry

The study of non-carbon containing compounds

Organic Chemistry

The study of carbon-containing compounds

Analytical Chemistry

Characterizes the composition of matter

Biological Chemistry (Biochemistry)

Chemical processes related to living organisms

Physical Chemistry

Principles of physics involved in chemical reactions (typically relates to math and energy)

Qualitative Observations

Descriptions of characteristics or behavior of nature (the diet soda feels lighter and sounds fizzier than the regular soda)

Quantitative Observations

Comparison of a characteristic or behavior of nature to a standard numerical scale (The diet soda weighs 355 grams vs the regular soda which weighs 375 grams)

Hypothesis

Statement proposed without actual proof to explain observations or their relationship (can be tested and proven wrong)

Experiment

Highly controlled procedure used to test whether a hypothesis is valid or invalid (accept or reject)

Scientific Law

Statement based on repeated observations or experiments that describes WHAT nature does

Scientific Theory

Explanation for observations based on evidence from numerous experiments that describes WHY or HOW nature happens

Substance

Specific instance of matter that can be classifed based on STATE and COMPOSITION

The physical form of matter includes these four:

Solid, liquid, gas, and plasma

The basic composition of matter includes:

Particles that make it up

Solids

Tightly packed in a regular, fixed pattern where particles vibrate in place but do NOT move around

Liquids

Particles are close together, not in a fixed pattern but slide past each other and can move more freely than solids

Gases

Particles are very spread out, randomly arranged, and move quickly in all directions while bouncing off each other and the container walls

Plasma

Particles are charged. far apart, and move very fast. Collisions cause electrons to seperate from atoms

Pure Substance

Composed of one type of matter, where all samples have the same characteristics

Mixture

Composed of two or more types of matter in which samples have different characteristics and can be seperated by physical methods

Element

Cannot be broken down into simpler substances by chemical changes

Compounds

Two or more elements that are chemically combined (fixed)

Homogenous Mixture (aka Solutions)

Uniform composition (examples include air, coffee, vinegar, blood, etc.)

Heterogeneous Mixture

Variable composition (examples include Pizza, Salads, Cookies, etc.)

Physical Property

Characteristic of matter that can be observed/measured without changing the chemical identity of the substance

Examples of Physical Property

Shape, length, mass, odor, volume, pressure, etc.

Physical Change

Change in the state or properties of matter without changing the chemical identity of the substance

Examples of Physical Change

Freezing, melting, condensing, evaporating, etc.

Chemical Property

Characteristic of matter that can be observed or measured by changing the chemical identity of the substance

Examples of Chemical Property

Flammability, toxicity, acidity, and corrosiveness

Chemical Change

Change in the state or properties of matter (atoms rearrange into new molecules, but all of the original atoms are still present)

Examples of Chemical Change

Rusting, photosynthesis, digestion