States of Matter Solid- It has its own definite shape and volume. The particles are tightly packed and may not conform to its container. Liquid- A form of matter that flows, has a constant volume, and takes the shape of its container. The particles are less tightly packed than a solid. Gas- It flows to conform to the shape of its container and fills the full volume. Particles are freely flowing. Gases are easily compressed.
Physical Property Extensiveproperties- It depends on the amount of substance present. Mass, length, and volume are examples. Intensive properties- It is independent of the amount of substance present. Density is an example.
Chemical Property The definition of a chemical property is the ability or inability of a substance to combine with or change into one or more new substances. Iron rusting and spoiled food are examples of a chemical property.
Physical and Phase Change A physical change is a change which alters a substance without changing its composition. The water cycle is an example of a physical change. A phase change is a transition of matter from one state to another. Substances usually undergo a phase change when temperature and pressure change. Melting, freezing, evaporation, and condensation are examples of phase changes.
Law of Conservation of Matter Thislaw states that mass is neither created nor destroyed during a chemical reaction. However, the matter is conserved. The mass of the reactants will always equal the mass of the products with no exceptions. Equation- mass reactants = mass products
MixturesA mixture is a combination or two or more pure substances in which each pure substance retains its individual chemical properties. There are two types Homogeneous Heterogeneous
Heterogeneous MixturesA heterogeneous mixture is a mixture that does not blend smoothly throughout and in which the individual substances remain distinct. Its composition is not uniform. Examples of a heterogeneous mixture is salad dressing mixture and orange juice.
Homogeneous MixtureA homogeneous mixture is a mixture that has a constant composition throughout. It always has a single phase. Also known as solutions which they can be solid, liquid, or a gas. A solid-solid solution is known as an alloy. Examples of a homogeneous mixture are tea, lemonade, bronze, and pewter.
Separating Mixtures Filtration- A technique that uses a porous barrier to separate a solid from a liquid. Distillation- A separation technique that is based on differences in the boiling points of the substances involved. Crystallization- A technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance.
Separating Mixtures cont. Sublimation-The process during which a solid changes directly to a gas without ever going through the liquid phase. Chromatography- A technique that separates the components of a mixture based on the ability of each component to travel or be drawn across the surface of another material.
Elements An element is a pure substance that cannot be separated into simpler substances by physical or chemical means. Each element has a unique chemical name and symbol. The symbol consists of one, two, or three letters.
The Periodic Table The periodic table organizes all of the elements into one chart. The horizontal rows are called periods. The vertical rows are called groups or families. Elements in the same group have similar chemical and physical properties. The table is called periodic because the pattern of similar properties repeats from period to period.
CompoundsA compound is made up of two or more different elements that are combined chemically. Most matter in the universe exists in the form of compounds. The chemical symbols of the periodic table make it easy to write the formulas for chemical compounds. Compounds cane be broken down. Example of a compound is table salt- NaCl
Law of Definite Proportions The Law of Definite Proportions states that a compound is always composed of the same elements in the same proportion by mass, no matter how large or small the sample. The mass of the compound is equal to the sum of the masses of the elements that make up the compound. The relative amounts of the elements in a compound can be expressed as percent by mass which is the ratio of the mass of each element to the total mass of the compound expressed as a percentage.
Law of Multiple Proportions The Law of Multiple Proportions states the when different compounds are formed by a combination of the same elements, different masses of one element combine with the same relative mass of the other element in a ratio of small whole numbers. Ratios compare the relative amounts of any items or substances.
Law of Multiple Proportionscont. The comparison can be expressed using numbers separated by a colon or a fraction. With regard to the law of multiple proportions, ratios express the relationship of elements in a compound. An example of the law of multiple proportions is water and hydrogen peroxide.
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