What is Chemistry? The study of the composition

of matter and the changes that matter undergoes.

Living and nonliving things are made of matter, chemistry affects all parts of life and most natural events.

Areas of Study Organic Chemistry- The study of all chemicals containing carbon.

Inorganic Chemistry- Study of chemicals that do not contain carbon.

Biochemistry- Focuses on processes that take place in organisms.

Analytical Chemistry- The study that focuses on the composition of matter

Physical Chemistry- Deals with the mechanism, the rate, and the energy transfer that occurs when matter undergoes a change.

Pure and Applied Chemistry• Pure Chemistry- the pursuit of

chemical knowledge for its own sake.

• Applied Chemistry- research that is directed toward a practical goal or application.

Nylon and Aspirin are examples of the two.

Chemists use specific materials to meet specific needs.

Macroscopic- describes the world of objects that are large enough to see with the unaided eye

Microscopic- world of objects that can be seen only under magnification.

Scientific Method- a logical, systematic approach to the solution of a scientific problem. Steps in the scientific method include making observations, testing hypotheses, and developing theories.

Hypothesis - is a proposed explanation for an observation. A hypothesis is useful only if it accounts for what is actually observed. When experimental data does not fit a hypothesis, the hypothesis must be changed.

Experiment - a procedure that is used to test a hypothesis.

When you design experiments, you deal with variables, or factors that can change. The variable that you change during an experiment is the manipulated variable, or independent variable. The variable that is observed during the experiment is the responding variable, or dependent variable

Describing Matter Properties used to describe matter

can be classified as extensive or intensive.

Mass of an object- is a measure of the amount of matter the object contains.

Volume of an object- is a measure of the space occupied by the object.

Extensive property- is a property that depends on the amount of matter in a sample.

Intensive property- is a property that depends on the type of matter in a sample, not the amount of matter.

Identifying Substances

Substance- Matter that has a uniform and definite composition.

Physical property- is a quality or condition of a substance that can be observed or measured without changing the substance’s composition.

States of MatterThree states of matter are solid, liquid, and gas.

Solid- a form of matter that has a definite shape and volume. The shape of a solid doesn’t depend on the shape of its container. The particles in a solid are packed tightly together, often in an orderly arrangement. Solids are almost incompressible; that is, it is difficult to squeeze a solid into a smaller volume.

Liquids- take the shape of the container in which it is placed. Volume of a liquid is fixed or constant. A form of matter that has an indefinite shape, flows, yet has a fixed volume. Liquids are almost incompressible, but they tend to expand slightly when heated.

Gas- a form of matter that takes both the shape and volume of its container. Particles in a gas are usually much farther apart than the particles in a liquid. Because of the space between particles, gases are easily compressed into a smaller volume.

Vapor- describes the gaseous state of a substance that is generally a liquid or solid at room temperature, as in water vapor.

Physical changes- some properties of a material change, but the composition of the material does not change.

Physical changes can be classified as reversible or irreversible. Melting is an example of a reversible physical change.

Words such as boil, freeze, melt, and condense are used to describe physical changes.

Classifying Mixtures Mixture - is a physical blend of two or more

components. Mixtures can be classified as heterogeneous mixtures or as homogeneous mixtures.

Heterogeneous mixture - a mixture that is not uniform in composition, components are not evenly distributed throughout the mixture.

Homogeneous mixture - is a mixture in which the composition is uniform throughout. Another name for a homogeneous mixture is a solution. Many solutions a liquids, some are gas and some are solids.

Phase is used to describe any part of a sample with uniform composition and properties. By definition, a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases.

Separating Mixtures

The process that separates a solid from the liquid in a heterogeneous mixture is called filtration.

Distillation- a process used to separate dissolved solids from a liquid, which is boiled to produce a vapor that is then condensed into a liquid

Distinguishing Elements and Compounds Element- the simplest form of matter that has a unique set of properties, an element cannot be broken down into simpler substances by chemical means.

Compounds- contain two or more elements chemically combined. Compounds can be broken down into simpler substances elements can not.

Compounds can be broken down into simpler substances by chemical means, but elements cannot.

Chemical change is a change that produces

matter with a different composition than the

original matter. Heating is one of the processes used

to break down compounds into simpler substances.

Chemical Changes Chemical property- The ability of a

substance to undergo a specific chemical change. During a chemical change, the composition of matter always changes

Chemical Reaction- One or more substances change into one or more new substances.

A substance present at the start of the reaction is a reactant.

A substance produced in the reaction is a product.

Scientific MeasurementCh. 3

Measurement: is a quantity that has both a number and a unit. Everyone makes and uses measurements.

scientific notation: a given number is written as the product of two numbers: a coefficient and 10 raised to a power. For example, the number 602,000,000,000,000,000,000,000written in scientific notation is 6.02 × 1023

Accuracy: is a measure of how close a measurement comes to the actual or true value of whatever is measured.

Precision: is a measure of how close a series of measurements are to one another.

The percent error is the absolute value of the error divided by the accepted value, multiplied by 100%.

There is a difference between the accepted value, which is the correct value based on reliable references, and the experimental value, the value measured in the lab. The difference between the experimental value and the accepted value is called the error.