Chapter 1

classification of mixtures

SLIDE 10

the standard units

Slide 16

Matter

1. is anything that has mass and occupies space. 2. We call a specific instance of matter: air, water, sand- a substance. 3. we classify matter according to its state(physical form) and its composition(the basic components that make it up)

energy of matter

1.all matter possesses energy 2.energy is classified as either kinetic or potential 3.energy can be converted from one form to another 4.whatever process you do that converts energy from one type or form to another, the total amount of energy remains the same (law of conservation of energy)

Gaseous matter

A+M have a lot of space between them and are free to move relative to one another, making gases compressible.

liquid matter

A+M pack about as closely as they do in solid matter, but they are free to move relative to each other, giving liquids a fixed volume but not a fixed shape. (assume the shape of their containers)

Scientific Method

Observation-Hypothesis-experiments- 1. scientific law(principle) 2. law of conservation of mass(principle) 3. theory 4. returns to observations to test theories Pages 3-4

mixtures into two types: 1. Heterogeneous 2.Homogeneous

heterogeneous: one in which the composition varies from one region of a mixture to another.(wet sand) homogeneous: one of the same compound throughout.(sweetened tea)

thermal energy

is a type of kinetic energy because it is associated with the motion of the individual atoms or molecules that make up an object.

law of conservation of energy

the idea that energy is neither created nor destroyed

classification of matter by composition

Matter: variable composition? yes:Mixture:1) made of multiple types of particles 2) samples may show different intensive properties no:pure substance:1) made of one type of particle 2) all samples show the same intensive properties

Molecules

a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.

Properties of Matter

determined by the atoms and molecules which compose it

accuracy

is an indication of how close a measurement comes to the actual value of the quantity

precision

is an indication of how reproducible a measurement is

classifying matter by physical shape

slide 6

Atomic Theory

the theory that all matter is made up of tiny indivisible particles (atoms). According to the modern version, the atoms of each element are effectively identical, but differ from those of other elements, and unite to form compounds in fixed proportions.

Atoms

are sub-microscopic particles that are the fundamental building block of ordinary matter. (free atoms are rare in nature)

Solid matter

atoms or molecules are pack together closely to each other in fixed locations. although the A+M vibrate, they don't move around or pass each other.

Chemical changes

changes that alter the composition of the matter

Physical change

changes that alter the state or appearance of the matter without altering the composition

Mixture

composed of two or more components in proportions that can vary from one sample to another. (ex. sweetened tea)

pure substances into two types: 1. element 2. compound

element: a substance that cannot be chemically broken down into simpler substances compound: a substance composed of two or more elements in a fixed, definite proportion.( more common than pure elements)

chemical property

is a property that a substance displays only by changing its composition via a chemical change. chemical properties include: corrosiveness, flammability, acidity, toxicity, and other such characteristics.

physical property

is a property that a substance displays without changing its composition. physical properties include: odor, taste, color, appearance, melting point, boiling point, and density.

Pure substances

substances that cannot be broken down into simpler substances by chemical reactions are called elements basic building blocks of matter composed of single type of atom though those atoms may or may not be combined into molecules • substances that can be decomposed are called compounds chemical combinations of elements composed of molecules that contain two or more different kinds of atoms all molecules of a compound are identical, so all samples of a compound behave the same way • most natural pure substances are compounds SLIDE 9

Chemistry

the science that seeks to understand the behavior of matter by studying the behavior of atoms and molecules.

kinetic energy and potential energy

total energy of an object is a sum of its kinetic energy and its potential energy. objects or systems with high potential energy tend to be unstable, but after the weight falls to the ground, it contains less potential energy, it becomes more stable.

separating mixtures

water&sand:decanting: carefully pouring off the water into another container. homogeneous mixtures and liquids can usually be separated by distillation, a process in which the mixture is heated to boil off more volatile(easily vaporizable) liquid. the volatile liquid is then recondensed in a condenser and collected in a separate flask. if a mixture is composed of an insoluble solid and liquid, we can separate the two by filtration, in which the mixture is poured through filter paper in a funnel.