Honors Chem Ch 1

Material

Material

matter that takes up space and resists changes to motion

Chemistry

study of material, its properties and changes

Submicroscopic

things we cannot see- atomic level (combusting is occurring - chemical bonds are being broken)

Macroscopic

things we can see with our senses (can see a flame and smell the burning)

Properties of matter depend on:

composition or kinds of elements AND on atom arrangement (H20 and H2O2)

Gas (unlike liquid and solids) are

able to be compressed

Gas has

no fixed volume OR shape

Gas particles move in a

chaotic movement spaced far apart

Liquid has

fixed volume but NOT fixed shape

Liquid particles are

closer together and slide past each other

Liquids and Solids are

NOT COMPRESSIBLE

Solids have

a fixed volume AND a fixed shape

Solid particles are

closer together and they vibrate in their individual places (submicroscopic)

A Pure substance can be composed of

elements or compounds

Elements are

one type of atom (can be found on the periodic table)

Elements cannot be

broken down

Elements are hard

to find naturally in the environment

Compounds are

composed of 2 or more atoms that are CHEMICALLY bonded together

Compounds have to

be in fixed proportions or ratios

A mixture is

a combination of 2 or more pure substances that ARE NOT chemically bonded together

Since mixtures are not chemically bonded

they are easier to separate

Mixtures...

... do not have to be in fixed proportions or ratios

A heterogeneous mixture

does NOT have the same composition, properties and appearance throughout

Examples of a heterogeneous mixture

sand, tile

A homogeneous mixture

are the same throughout, uniform

Another word for a homogeneous mixture is

solution

Examples of homogeneous mixture

gasoline, brass

Law of Definite Proportions

the fixed ratio of compounds (H20 two hydrogens for every oxygen)

Properties are what

allow you to recognize and distinguish one substance from another

Physical properties

can be measured without changing the identity and composition of the substance

Physical properties are typically viewed on the

macroscopic level

Examples of Physical Properties

color, odor, density, boiling point

An individual atom DOES NOT posses a

individual physical property. An individual atom does not have color or a boiling point.

Chemical properties are

the way that a substance may change or react to another substance.

An example of a chemical property is

flammability, the ability to burn in the presence of oxygen

A substance will have a changed chemical symbol when ________ properties are being tested.

Chemical

Intensive properties are

INdependent on the amount of substance present

Examples of intensive properties

density or boiling point (1 cup of water and 1 gallon of water both boil at 100*C)

Extensive properties are

dependent on the quantity (amount) of substance present

Examples of extensive properties

mass and volume (the more stuff you have the more mass or volume there will be)

Changes can be classified into two categories

physical and chemical

Physical Changes

change in appearance but not chemical composition

Examples of physical changes

Change in state (Gas-Liquid-Solid) and dissolving of salt (can evaporate water and salt is still there) chopping something up

Chemical Changes

change in chemical composition

How can you tell a chemical reaction occurred? (MUST KNOW)

All 5 are unexpected

1. Gas forms (bubbles)

2. Precipitate forms

3. Heat

4. Light

5. Color change

Examples of chemical changes

burning, rusting, fermenting (cheese, wine)

Chemical changes are also called

chemical reactions

Quantitative observations contain

a number and a unit (15.5 g)

Qualitative observations contain

a word description (the stick was very long)

Hypothesis is a

possible explanation for an observation

Personal and small in scope

hypothesis

Hypothesis are used to

plan future experiments

Hypothesis's and theories are

subject to revision

Hypothesis's can be

proven right or wrong

In short, a hypothesis is

a smaller idea and pre-experimental and attempts to answer why

Theory is

an overall explanation of certain phenomena

Theories need

considerable experimental evidence or observations to support it

A theory provides

background information for a hypothesis

A big general idea that is large in scope

theory

A hypothesis is tested

via experimentation

Theories cannot

be proven via experimentation

A theory can never be

proven correct absolutely correct but has not yet been proven wrong

Theories are used to

make predictions

Natural Law

is a statement that summarizes generally observed behavior.

Natural Law is NOT

an explanation of the facts.

Natural Laws are

supported by a large body of experimental results

Derived Units

consist of a combination of base units

1 cm^3 =

1 mL

1 dm^3

1 Liter

Density=

mass/volume

Precision measures

how closely individual measurements agree with one another.

To determine precision

you need to repeat the same test many times

Precision is an indicator of

random error

Random Error

is random and that an error in measurement has an equal chance of causing your result to be high or low

Accuracy measures

how closely individual measurements agree with the correct value

Giga (G)

1x10^9

Mega (M)

1x10^6

Kilo (k)

1x10^3

Deci (d)

1x10^-1

Centi (c)

1x10^-2

Milli (m)

1x10^-3

Micro (µ)

1x10^-6

Nano

1x10^-9

Unit for Mass

kilogram

kilogram abbreviation

kg

Unit for Length

Meter

Meter abbreviation

m

Unit for Time

Second

Second abbreviation

s

Unit for Temperature

Kelvin

Kelvin abbreviation

K (uppercase)

Unit for Amount of Substance

Mole

Mole abbreviation

mol

Unit for Electric Current

Ampere

Ampere abbreviation

A (uppercase)

Unit for Luminous Intensity

Candela

Candela abbreviation

cd