Unit 1 Chem Terms

dimensional analysis

a mathematical technique that allows you to use units to solve problems involving measurements

conversion factor

a fraction in which the top equals the bottom- used for canceling units

temperature

a measure of average kinetic energy

absolute zero

the point in which a substance has no motion. this is the coldest an object can be

density

the ratio of mass of an object to the volume

specific gravity

a comparison of the density of a substance to the density of a reference substance, usually at the same temperature

accepted value

information given to be true

experimental value

information obtained in a experiment

error

accepted value minus experimental value

percent error

the absolute value of the error divided by the accepted value, multiplied by 100%

matter

Anything that has mass and takes up space

mass

the amount of matter in an object

solid

A state of matter that has a definite shape and volume

liquid

A state of matter that has a definite volume but no definite shape.

gas

A state of matter with no definite shape or volume

property

any characteristic of something that we can use to identify and recognize the thing when we see it again

physical property

a quality or condition of a substance that can be observed or measured without changing the substance's composition

physical change

an alteration of a substance without changing its composition

chemical property

the ability of a substance to undergo chemical reactions and to form new substances

chemical change

a change in the fundamental components of a substance

elements

the simplest form of matter that can exist under normal lab conditions

compound

two or more different elements chemically bonded

mixture

consist of a physical blend of two or more substances

heterogenous mixture

a mixture that appears to be made of different substances

homogeneous mixture

a mixture that appears to be only one substance

colloid

a substance is which microscopically dispersed insoluble particles are suspended throughout another substance

Tyndall effect

The scattering of light due to the large size of the particles in a colloid

solution

A homogeneous mixture at the atomic or molecular level

solute

the part that gets dissolved. has apparent phase change

solvent

the part of the solution that does the dissolving. no apparent phase change

distillation

A process used to separate a mixture of substances. the mixture is boiled and then condensed again to a liquid. the substances are separated by difference in boiling point

filtration

a mixture poured on a mesh, such as filter paper which allows the liquid to pass through and leaves the solid behind.

chromatography

process for separating components of a mixture. is dissolved in a substance called the mobile phase, which carries it through a second substance called the stationary phase.

quantitative measurements

give results in a definite form, usually as numbers

qualitative measurements

results are description in nonnumerical form

theory

a thoroughly tested and detailed explanation of why experiments give certain results

(natural) Law

a statement that summarizes the results of a broad spectrum of observations and experiments

experiment group

Group with the experimental variable. Alike in every other way

control group

this group is alike in every way to the exp. group without the exp. variable

variable

anything that can change or vary from group to group

independent variable

variable that is purposely manipulated

dependent variable

variable directly measured

scientific notation

a number written as the product of two numbers a coefficient and a power of ten