Chemistry Midterm Review

Units 1-5

System

What is being measured

Surroundings

Anything outside of the system

Accuracy

How close a measurement is to the true value

Precision

How close a set of measurements are to one another

Density

Relationship between mass and volume (D=m/v)

Base to milli conversion

10⁻³

Base to kilo conversions

10³

Temperature

Average kinetic energy of the particles in a system

Pressure

Force of particle collisions divided by the area of its container

Specific Heat

The amount of energy required to raise the temperature of 1g of a substance by 1 degree

Heat of Fusion

Energy to melt/freeze 1g of a substance

Heat of Vaporization

Energy to vaporize/condense 1g of a substance

Endothermic

Thermal energy flows into the system from the surroundings

Exothermic

Thermal energy flows out of the system into the surroundings

Temperature and Volume Relationship

Directly Proportional (amount of gas and pressure are constant)

Volume and Pressure Relationship

Inversely Proportional (amount of gas and temperature are constant)

Temperature and Pressure Relationship

Directly Proportional (amount of gas and volume are constant)

Kelvin Conversion

Celcius + 273º

Thermal Expansion

As thermal energy increases, particles collide with greater force and take up more space

Particle Behavior as a Solid

Strong attractive force, moving a little in place

Particle Behavior as a Liquid

Strong attractive force, slightly more spread out, able to move around each other

Particle Behavior as a Gas

Not orderly, little to no attractive force, spreading outwards to fill up the whole space

Pure Substance

Matter with a definite composition (element or compound)

Element

Simplest form of matter, not separated by physical or chemical means

Compound

Two or more elements chemically bonded, separated by chemical means

Molecule

Two or more atoms of the same element bonded together

Mixture

Physical blend of two or more components, separated by physical means

Heterogeneous Mixture

Mixture that doesn’t have a uniform composition throughout

Homogeneous Mixture

Mixture that does have a uniform composition throughout

Mole

A quantity, 6.02x10²³

Filtration

Heterogeneous mixtures: separating solid from liquid

Distillation

Liquid is boiled to evaporate and then condense

Proton

Particle with positive charge, inside of the nucleus

Electron

Particle with negative charge, outside of the nucleus

Neutron

Particle with no charge, inside of the nucleus

Nucleus

Where protons and neutrons are, dense center of atom

Isotope

Atoms of the same element with different number of neutrons

Gold Foil Experiment (Rutherford)

Rutherford shot positive particles at a thin gold sheet, they deflected in all different directions, ones that went through showed atom is mostly empty, ones that deflected showed atom has a dense positive nucleus

Isotope Notation

Mass number on top, atomic number on the bottom

S orbitals

1s orbital per sublevel, 2 electrons

P orbitals

2p orbitals per sublevel, 6 electrons

D orbitals

5d orbitals per sublevel, 10 electrons

Mass Number

# of protons + # of neutrons

Atomic Mass

Weighted average of all naturally occurring isotopes of the element

Democritus/Dalton Model

Solid sphere, no internal structure

Plum Pudding Model

Ball of positive energy with negative charge stuck throughout

Planetary

Dense positive nucleus with electrons orbiting

Bohr

Dense positive nucleus with electron energy levels surrounding

ROYGBIV

Increasing energy from R to V

Atomic Radius Group Trend

Going down a group, atomic radius increases

Atomic Radius Group Reasoning

More energy levels are added going down the group

Atomic Radius Period Trend

Going across a period, atomic radius decreases

Atomic Radius Period Reasoning

Adding electrons to same electron level, protons added make nucleus stronger and more attractive

Ionization Energy Group Trend

Going down a group, ionization energy decreases

Ionization Energy Group Reasoning

Easier to remove electrons because they are further away from the nucleus and there is less of a pull

Ionization Energy Period Trend

Going across a period, ionization energy increases

Ionization Energy Period Reasoning

Nucleus gets more positive, more pull on the electrons, more difficult to remove

Small wavelength corresponds to

High energy ROYGBIV

Large wavelength corresponds to

Low energy ROYGBIV

Large frequency correspond to

High Energy ROYGBIV

Ion

Charged atom made by adding or removing electrons

Ionic Compound

Chemical compound of ions held together by an ionic bond

Ionic Bond

Electrostatic attraction between oppositely charged ions

Polyatomic Ion

A group of atoms bonded together that have an overall charge

Formula Unit Usage

referring to an ionic compound. molecules are discrete units that are separate, ionic compounds form in a lattice pattern. formula unit is the smallest whole number ratio between ions in a structure.

Metallic Character/Reactivity Group Trend

Going down a group, metallic character/reactivity increases

Metallic Character/Reactivity Group Reasoning

Measure of how easy it is for elements to lose their electrons, electrons get further away as you go down a group

Metallic Character/Reactivity Period Trend

Going across a period, metallic character/reactivity decreases

Metallic Character/Reactivity Period Reasoning

Measure of how easy it is for elements to lose their electrons, valence shells fill up and the increasingly positive nucleus draws them in making them harder to remove

Heat

Flow of energy due to temperature difference between systems

Thermal Energy

Energy “contained” in a substance due to particle movement