CHEM 100

Ch 2-4

Physical States of SOLIDS

Definite fixed shape, definite fixed volume, tight packed atoms, incompressible (does not change by pressure or force)

Physical States of LIQUIDS

indefinite shape (not fixed), fixed volume (stays the same), incompressible /does not change by pressure or force, lightly loosely packed atoms

Physical State GAS

indefinite shape (not fixed shape), indefinite volume (can take shape of what you put it in), compressible = can be changed/reduced in volume under pressure, Atoms very far apart and loosely packed.

What’s the formula to convert Celsius into Fahrenheit?

Tf = 9/5 (Tc + 32)

When a SOLID is converted directly into GAS the change of state is called

Sublimation

when a GAS is converted directly into a SOLID the change of state is called

deposition

when a GAS is converted directly into a LIQUID the change of state is called

Condensation

A physical change is

is a change in the form, size, shape, or state of a substance without changing its chemical identity.

Physical change vs Chemical change

Physical vs. Chemical Change

Physical Change

• Melting ice

• Tearing paper

• Boiling water

Chemical Change

• Burning wood

• Rusting iron

• Cooking an egg

The Law of Conservation of Mass states:

Mass cannot be created or destroyed in a chemical reaction.If you react

• 10 g of hydrogen

• 80 g of oxygen

Then you must end up with:

10 g+80 g=90g

What is the law of conservation of energy?

Energy cannot be created or destroyed; it can only be transferred or converted from one form to another.

• Conservation of Mass:

• Conservation of Mass: Matter cannot be created or destroyed.

• Conservation of Energy:

• Conservation of Energy: Energy cannot be created or destroyed.

• Conservation of Mass and Energy:

• Conservation of Mass and Energy: The total amount of mass and energy remains constant.

The Law of Constant Composition

A pure compound always contains the same elements in the same fixed proportions by mass. Constant Composition → A compound always has the same composition.

What is the term for a pure substance that cannot be broken down any further by ordinary chemical reaction?

Element (cannot be broken down simpler) and is a pure substance

What is Atomic Properties

• Atomic number = number of protons

• Atomic mass = mass of the atom (protons + neutrons, approximately)

• Number of protons

• Number of neutrons

• Number of electrons

• Atomic radius = size of the atom

• Charge = whether the atom is neutral, positive, or negative

Chemical Properties

Only when a chemical reaction occurs/when a substance undergoes a chemical change to form a new substance:

• Flammability (ability to burn)

• Reactivity with oxygen (rusting)

• Reactivity with acids

• Ability to corrode

• Toxicity

A molecular property is :

A molecular property is a characteristic of a molecule that depends on its structure, shape, or the atoms it's made of.

A physical property

Physical Property = is a characteristic of a substance that can be observed or measured without changing the substance into a new substance.

The primary substances of which all other things are composed are:

Elements

The smallest particle of an element that retains the characteristics of an element is:

Atom

Neutron

is a subatomic particle found in the nucleus (center) of an atom.

Electron

is a subatomic particle that moves around the outside of the nucleus of an atom.

Properties:

• Charge: -1 (negative)

• Location: Outside the nucleus (electron cloud)

• Mass: Very small (about 1/1836 the mass of a proton)

Proton

is a subatomic particle found in the nucleus (center) of an atom.

Properties:

• Charge: +1 (positive)

• Location: Nucleus

• Mass: About 1 amu (atomic mass unit)

Protons determine the :

Element

Neutrons determine the :

isotope

Electrons determine the :

Charge

A Subatomic Particle is:

is a particle smaller than an atom Ex: protons (in nucleus), neutrons (in nucleus), electrons (outside nucleus)

Atomic number = the number of

Protons

How do you get the Mass #?

By adding protons + neutrons

The number of Protons = the number of

Atomic Number

What equation do you need to find # of Neutrons?

Mass # - Atomic # = Neutrons

Isotopes of each other you must look for =

having the same atomic number/same protons but the isotope number/mass number can be different

If there is no charge (exponent) or if its 0 then its neutral and protons =

same number of electrons

Electron levels are

the rings around the atoms (energy levels) ex: magnesium has 3 rings of electrons

Valence electrons are

electrons from the most outershell

Core electrons are:

all other inside electrons after the outer most shell

Scientific Notation

write out large numbers smaller with exponents

Standard Form/notation

Is moving the decimal and making the number show