chemistry test 1

density

density

measurement of how tightly a material is packed together

states of matter

distinct form in which matter can exist

solid

firm and stable in shape, particles are tightly packed, cannot be pressed into a smaller volume

liquid

flows freely but is of constant volume, particles are not held in place and are less closely packed than the solids

gas

substance or matter which can expand freely, no fixed shape, its particles are far apart

vapor

substance diffused or suspended in the air, normally liquid or solid at room temp

physical property

characteristic of a substance that can be observed or measured without changing the identity of the substance, pure substance

extensive property

property that depends on the amount of substance present like size or weight

intensive property

one that does not depend on the amount of a substance like temperature or boiling point

chemical property

characteristic of a substance that may be observed when participating in a chemical reaction, ability or inability of a substance to mix with or change into another substance

why do we use physical properties more than chemical ones?

they can be identified without having to use a chem reaction

resource

total amount of a natural substance

observation

info gathered with the senses

physical change

change in size or form, its composition stays the same

phase change

conversion of matter from one state to another

chemical change

change of materials into another, new materials with diff properties

law of conservation of mass

states that mass is neither created nor destroyed in a chemical reaction

rusting

electrochemical reaction

mass of products = mass of reactants

law of conservation of mass formula

proportion

equality between 2 ratios

element

pure substance that cannot be separated into a simpler substance

periodic table

array of chemical elements organized by atomic number

compound

substance made up of two or more different chemical elements combined in a fixed ratio

law of definite proportions

states that a compound is always composed of the same elements in the same proportion by mass

percent by mass

ratio of the mass of each element to the total mass of the compound expressed as a percentage

law of multiple proportions

states that when diff compounds are formed by the same elements, diff masses of 1 element with the same fixed mass of the other element

electrolysis

process of using electricity to split water into hydrogen and oxygen

substance

uniform and unchanging composition, also known as a pure substance

plasma

form of matter that results when particles of a gas are ionized and are broken apart into smaller particles

mixture

combination of pure substances

heterogeneous mixture

mixture that does not blend smoothly, individual substances remain distinct

homogeneous mixture

referred to as solutions, mixture that has a constant composition, single phase

alloy

homogeneous mixture of metals

filtration

technique used to separate a solid from a liquid

distillation

physical separation technique that is based on differences in boiling points

sublimination

process where a solid changes into vapor, without melting