CSUN Chemistry 101 - test 1 prep (chapter 1)

How are properties of matter determined?

by the properties of atoms and molecules

properties of matter examples

color, smell, toxicity

Small changes of particles result in...

big changes in their behavior

Atoms

submicroscopic particles that are the fundamental building blocks of matter

Molecule

atoms bonded together in a specific geometrical arrangements to form molecules

Water vs. Hydrogen Peroxide

H2O vs H2O2

Same elements, but different composure and behavior

Chemistry

the science that seeks to understand the behavior of matter by studying the behavior of atoms and molecules

Diamond vs. Graphite

-Chemical composition both only Carbon

- Different crystal structure, vastly different physical properties

- Different amount of carbon

scientific approach to knowledge (SAtK)

based on observation and experiment

Hypothesis

-explanation of observation

- is falsifiable

- test with experiments that can be either supported or proven incorrect

Scientific Laws

-Series of similar observations

-summarizes past observations and predicts future observations

- have experiments to prove

- describes how nature behaves

- also known as principals

Law of Conservation of Mass

Matter is not created nor destroyed in any chemical or physical change

Theory

- model for the way nature is and why

- pinnacle of scientific knowledge

-explains lots and observations

atomic theory

matter is composed of tiny particles called atoms.

scientific approach to knowledge begins and ends with...

observations

How many states of matter are there

three

what are the states of matter

solid, liquid, gas

Solids is

- don't move around or pass one another

- fixed volume and shape

Liquids is

- free to move around

- fixed volume

- takes the shape of the container

Gas is

- lots of space to move around

- compressible

Types of Composition

pure substance and mixture

What are the two types of mixtures

homogeneous and heterogeneous

what are the two types of pure substances

elements and compounds

Matter

anything that has mass and occupies space

Substance

specific instance of matter

crystalline

atoms of molecules are in patterns w/ long range repeating order

Crystalline examples

table salt, diamond crystals

amorphous

doesn't have a long range of order

amorphous example

glass or plastic

pure substance

- only one component

- individual atom or group of atoms

Mixture

- two or more components

-vary from one to another

- more than 1 type of molecule

types of pure substances are determined by

if they can be broken down into a similar form

Elements

cannot be broken down into simpler substances

example of an element

name anything off of the periodic table

compounds

two or more elements in a fixed proportion

Example of a compound

water, salt, sugar, etc

types of mixtures are determined by

how they mix and the composition of the mixture

hetergeneous

(adj.) composed of different kinds, diverse

heterogeneous examples

cereal in milk

vegetable soup

pizza

ice in soda

salad dressing

mixed nuts

homogeneous

of a similar kind

examples of homogeneous mixtures

saltwater, milk, fog, lemonade

How are mixtures separated?

physical means based on their properties

How many ways can you separate a mixture

3

what are the three types of separating mixtures

decanting, distillation, and filtration

Decanting

pour water into another container

what type of mixture goes through decanting

Heterogeneous

Distillation

mixture is heated to boil and volatile

what kind of mixture goes through distillation

Homogeneous

Filteration

mixture is poured through a filter

Is filtration soluble or insoluble?

insoluble

Examples of changes of matter

ice melting, iron rusting, gas burning, fruit ripens, water evaporators

Physical changes

Any change that DOES NOT alter the chemical composition of a substance.

examples of physical changes

Melting butter, tearing paper, crushing a can, freezing water, dissolving koolaid, cutting your hair.

chemical changes

A change in which one or more substances combine or break apart to form new substances.

example of physical changes

iron and sulfur are heated, they react to create a compound, iron sulfide

physical property

property does not change

chemical property

changes the composition via chemical change

Do physical changes and chemical changes have energy changes? Give an example

yes

- Water evaporates from your skin to cool you down

Energy

the capacity to do work

Work

the action of a force through a distance

Total energy

potential energy + kinetic energy

kinetic energy

energy of motion

example of kinetic energy

A ball rolling down a hill

potential energy

stored energy that results from the position or shape of an object

example of potential energy

a ball at the top of a hill

thermal energy

Heat energy

example of thermal energy

ice cream melting

Law of Conservation of Energy

Energy cannot be created or destroyed

Can energy change from one type to another?

yes

does the total quantity of energy stay the same

yes

are systems with high potential energy stable or unstable?

unstable

what happens when gasoline goes through combustion

the arrangements of these particles change and create molecules of lower potential energy to the surroundings

SI Units

International System of Units

Sig Figs

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

unit

a standard quantity used to specify measurements

Where is the metric system used?

most of the world

where is the English system used

used in the USA

International System of Units

a system of measurement based on the metric system

standard unit

an established quantity used for measure and comparison

derived unit

A unit defined by a combination of base units

example of a derived unit

m/s for speed

Volume

The amount of space an object takes up

Density

the ratio of the mass of a substance to the volume of the substance

intensive property

independent of the amount of substance present

extensive property

depends on the amount of matter in a sample

How does a scientific report measure quantaties

- number of digits reflect the certainty

more digits= more ???

Certainly

uncertain digit

always the last digit

What is the uncertain digit in 5.213

3

Meniscus

Curved surface of liquid

where do you measure the meniscus

bottom of the curve

Sigfigs

a measurement consisting of all the digits known with certainty plus one final digit, which is somewhat uncertain or is estimated

exact number

have no uncertain digits

accurate counting

counting the amount

example of accurate counting

3 atoms= 3.00000... atoms

defined quantities

# of cm in 1 meter

example of defined quantities

100 cm in 1 m

integral numbers

part of an equation

examples of integral numbers

radius = diameter/2

sig figs for multiplication and division

fewest sig figs