Mastering Chemistry Chapter 1 & 2

Chemistry

The study of the properties of matter and how matter changes

Matter

Anything that has mass and takes up space

Matter

the physical material of the universe

gas

no fixed volume or shape, compressible, fast moving molecules

solid

fixed volume and shape, incompressible, definite, fixed arrangement, vibrate in place

elements

cannot be decomposed further

atoms

Building blocks of matter

compound

made of atoms from two or more different elements

mixtures

exhibit the properties of the individual substances that they are made of.

heterogeneous

(adj.) composed of different kinds, diverse

homogeneous

of the same kind

physical properties

can be observed without changing a substance

chemical properties

can only be observed when a substance is changed into another substance

intensive property

independent of the amount of substance present

extensive property

depends on the amount of matter in a sample

physical change

A change in a substance that does not involve a change in the identity of the substance

chemical change

A change in matter that produces one or more new substances

Energy

the ability to do work or transfer heat

work

Force exerted on an object that causes it to move

heat

the energy used to cause the temperature of an object to increase

Force

A push or pull exerted on an object

kinetic energy

energy of motion

potential energy

stored energy; depends on the relative position compared to other objects.

Quantitative

Data that is in numbers

Celsius scale

temperature based on the properties of water

Kelvin scale

SI unit for temperature

exact numbers

numbers counted or given by definition

inexact numbers

numbers that depend on how they were determined

Accuracy

A description of how close a measurement is to the true value of the quantity measured.

Precision

a measure of how close a series of measurements are to one another

sig figs

All the digits that can be known precisely in a measurement, plus a last estimated digit

Addition or Subtraction

answers are rounded to the least significant decimal place

Multiplication or Division

answers are rounded to the same number of digits as the measurement with the fewest number of sig figs.

dimensional analysis

used to change units

Law of Conservation of Mass

Matter is not created nor destroyed in any chemical or physical change, but merely changes form

Law of Multiple Proportions

if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers

move from negative to positive

cathode rays

Thomson

Credited with the discovery of the electron/cathode rays

Milikan

determined the charge of the electron

Radioactivity

the spontaneous emission of high-energy radiation by an atom

Thomson

came up with the plum pudding model

protons

+1

Electrons

-1

Neutron

neutral

atomic number

the number of protons in the nucleus of an atom

mass number

the number of protons plus the number of neutrons

isotopes

atoms of the same element with different masses

12C

almost 99% of the carbon found in nature

4 x 10 -22

the mass of heaviest known atoms

periodic table

systematic organization of the elements

periods

rows on the periodic table

groups

columns on the periodic table

left

the side of the periodic table that metals are on

right

the side of the periodic table that nonmetals

empirical formula

give the lowest whole-number ratio of atoms each element in a compound

molecular formula

give the exact number of atoms of each element in a compound

structural formulas

show the order in which atoms are attached

ion

when an atom loses or gains electrons, it becomes this

cation

formed when at least one electron is lost

anion

formed when at least one electron is gained

polyatomic ion

when a group of atoms gains or loses electrons

ionic compound

compound formed between metals and nonmetals

organic chemistry

the study of carbon

alkanes

the simplest hydrocarbons

isomers

when two or more molecules have the same chemical formula but different structures