1.1-1.6 textbook notes

Science

A systematic way of studying the natural world based on empirical evidence- things we can measure

Scientific law

Concise summary of accepted facts of nature (what is always observed)

Scientific theory

concise & well-tested explanation of natural phenomena based on observation and experimentation (why it is observed)

Scientific method

Observation/question, hypothesis, experiment, conclusion

Matter

anything that occupies space & has mass

Chemistry

the science of matter, using the scientific method:

1.) composition

2.)structure

3.) properties, & the

4.) changes it undergoes (along with the energy involved)

Atom:

smallest particle of an element that retains the chemical properties of the element

Composition of matter

Specific combination of atoms, EX: C2H6O

Pure substance, element

Is P4 a pure substance or a mixture? is it an element or a compound?

Molecule

2 or more atoms chemically bonded together, (can be the same or different)

Structure of matter

how atoms are arranged spatially, EX: ethanol and dimethyl have either the same chemical composition, C2H6O, but have different structures

Chemical properties

how atoms react to other atoms, (can only be observed by doing the reaction which changes the identity of the material

Physical properties

characteristics that can be oberved or measured without changing the identity of the substance

Intensive properties

always the same

Examples of intensive properties

color, odor, density, electrical conductivity, & solubility (ability to dissovle)

extensive properties

depend on the amount of material present

example of extensive properties

length, width, mass, volume

physical state

state of the material at a certain temeprature

Solid

distinct volume & distinct shape

liquid

distinct volume, but no distict shape

gas

no distinct volume & no distinct shape

Deposition

gas to liquid

sublimation

solid to gas

melting

solid to liquid

vaporization

liquid to gas

condensation

gas to liquid

freezing

liquid to solid

Physical process

Doesn’t alter identity of the substance at atomic/molecular level (composition/structure remain the same)

Chemical reactions

alter identity of substance at atomic/molecular level (composition/structure change)

Chemica reaction

a process that changes the chemical identity - or composition and structure- of the material(s)

What are the three types of energy?

Potential, kinetic, and radiant

potential energy (PE)

energy stored in an object due to or its position or composition

Kinetic energy (KE)

energy of motion (KE = ½ MV2)

radiant energy

light

law of conservation of energy

energy cannot be created or destroyed, only converted grom one form to another, energy is often transferred as work or heat

What did the greeks believe?

atonomism, but died from lack of evidence, instead believed in avatar theory, 4 basic elements that gave rise to all matter

Alchemists

believed that 1 material could be transformed into another, so lead for centuries for ways to turn lead into gold. so chemistry was black magic.

Robert Boyle

rejected avatar theory and presented a hypothesis of modern view of elements

what did robert boyle argue?

that theories about matter should be based on obervation & demonstration

Antonie Lavoisier

built state-of-the art labratory with accurate scales, measured mass in all his experiments, and published the first chemistry textbook

Law of conservation of mass

stated that an equal quantity of matter exists both before and after the experiment

Law of definite proportions

In a given chemical compound, the proportions by mass of the elemnt that compose it are fixed, IE chemical composition always the same amount

Law of multiple proportions

When a given mass of a certain element can form compounds with 2 different masses of another element, the ratio of the 2 different masses involves small whole numbers