Chemistry1: The Science of Matter

Matter takes up space and has mass Mass is the amount of matter Properties of matter describe the

characteristics and behavior of matter Matter can be viewed as macroscopic

or microscopic Models connect the macroscopic and

microscopic views

Classifying Matter

Matter can be classified by composition: both qualitative and quantitative

Matter can be divided into pure substance or mixture

For pure substance, it is either element or compound

For mixture, it is either homogeneous or heterogeneous

Mixtures can be separated by physical means

Physical and chemical changes

Physical changes can separate mixtures into pure substances

Chemical changes involve combining atoms to form new compounds, usually heat is required

Elements are basic building blocks of compounds

All elements have been organized in the periodic table

Compounds

All compounds consist more than one element

A formula is a combination of chemical symbols that show what elements make up a compound and the number of atoms of each element

Properties and changes of matter

There are 4 states of matter: solid, liquid, gas, and plasma

Density is the mass contained in a unit of volume

Solids are denser than liquids because the molecules are closer together

Chemical changes can be endothermic or exothermic

Chemical Symbols

Each element is represented by a chemical symbol—consists of up to 2 letters—the 1st letter is always capitalized; the 2nd is always lower case.

Some have Latin names, such as Na, K, Sb, Cu, Au, Ag, Fe, Pb, Hg, Sn, W, etc.

Energy

Energy is the capacity for doing work Stored chemical energy is a form of potential

energy, the energy of position When a substance is burned, it is converted

into kinetic energy, the energy of motion Heat energy can be transferred from one body

to another because of a temperature difference

Conservation of Energy

The law of conservation of energy states that in any chemical or physical process, energy is neither created nor destroyed.

Chemical Reactions Energy changes occur whenever a chemical reaction

takes place. In a chemical reaction, one or more substances are changed into new substances.

The starting substances are called reactants, and the new substances are the products.

A solid that separates from a solution is called a precipitate.

The ability of a substance to undergo chemical reactions and to form new substances constitutes its chemical properties.

Conservation of Mass

The law of conservation of mass states that in any physical or chemical reaction, mass is neither created not destroyed; it is conserved.